User’s Manual for the ITEMAN™

Conventional Item Analysis Program

Manual for the 32-bit Windows Version 3.6

Assessment Systems Corporation

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System Requirements Personal computer running

Microsoft Windows 95/98/NT/ME/or XP 2 Mb free RAM

For Further Information Assessment Systems Corporation

2233 University Avenue, Suite 200 St. Paul, Minnesota 55114

Voice: 651-647-9220 FAX: 651-647-0412

E-Mail: support@assess.com www.assess.com

User’s Manual for the ITEMAN Conventional Item Analysis Program Second Edition, 32-bit Windows Version

Copyright © 1989-2006 by Assessment Systems Corporation All Rights Reserved

No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means—electronic, mechanical, photocopying, recording, or otherwise—without the

prior written consent of the publisher. .

ITEMAN is the Trademark of Assessment Systems Corporation. Windows is the Registered Trademark of Microsoft Corporation.

Chapter 1: Overview

Overview ITEMAN is one of the analysis programs that comprise Assessment Systems Corporation’s Item and Test Analysis Package. ITEMAN analyzes test and survey item response data and provides conventional item analysis statistics (e.g., proportion/percentage endorsing and item-total correlations) for each item, in order to assist in determining the extent to which items are contributing to the reliability of a test and which response alternatives are functioning well for each item. In addition to item-level statistics the ITEMAN program also provides statistical indicators on the performance of the test as a whole (e.g., mean, standard deviation, reliability, median p-value). See Chapter 3 for a complete description of the ITEMAN program and information on the specific statistical indicators available with ITEMAN.

This manual will tell you how to install and run the ITEMAN program. Although Chapter 3 describes each statistic that is computed, it assumes some knowledge of the proper use and interpretation of these statistics. You might wish to refer to a basic textbook on test theory and methods such as Crocker and Algina (1986) for a brief review if the terms in Chapter 3 seem unfamiliar to you.

Table of Contents To view the Table of Contents for this manual, select the Bookmark tab on the left side of the Acrobat window. The bookmark entries are hyperlinks that will take you directly to any section of the manual that you select.

References Crocker, L., and Algina, J. (1986). Introduction to classical and modern test theory. New York:

Holt, Rinehart and Winston.

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Chapter 2: Formatting Examinee Data

Overview

The ITEMAN program requires that input data be formatted in ASCII (text-only) files. This can be accomplished through the use of the ITEMAN for Windows text editor, Notepad, a word-processing editor that produces true ASCII output, or a program written specifically to format your data. All the data to be included in the analysis must be contained in a single input file. Up to 750 items can be included in a single analysis, while the number of examinees is virtually unlimited.

The File Format The proper format for the input file is similar for all the Item and Test Analysis Package programs. The only differences in format reflect the ability of ITEMAN to analyze more than one scale at a time and to analyze data for multipoint or rating-scale-type items. An example of a data file in the proper input format is shown in Figure 2-1.

Figure 2-1. Example Input File Containing Dichotomous Items 30 O N 5 143534243521132435241342351423 KEY 555555555555555555555555555555 NO. ALTERNATIVES YYYYYYYYYYYYYYYYYYYYYYYYYYYYYY ITEMS TO INCLUDE EX001543542143554321542345134332413 EXAMINEE #1 EX002143534244522133OO2542531342513 EXAMINEE #2 EX003143534223521132435244342351233 EXAMINEE #3 EX004143534243521132435241342352NNN EXAMINEE #4 EX005143534243412132435452132341323 EXAMINEE #5

A data file consists of five primary components: 1. A control line describing the data; 2. A line of keyed responses; 3. A line of the numbers of alternatives for the items; 4. A line specifying which items are to be included in the analysis; and 5. The examinee data.

Comments may also be included in the data file. Each of these elements is described in the following sections.

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The Control Line The first line of the data file must contain the following data in the columns specified:

Column Data 1-3 Number of items for which responses are recorded for each examinee

(maximum is 750) 4 Blank 5 Alphanumeric code for omitted responses 6 Blank 7 Alphanumeric code for items not reached by the examinee 8 Blank 9-10 Number of characters of identification data recorded for each examinee

(maximum is 80)

In columns 1-3, you must enter the number of items that are included in the file. This number must be right-justified: The “units” go into column 3, the “tens” in column 2, and the “hundreds” in column 1. A maximum of 750 items can be handled by ITEMAN Figure 2-1 shows a data file with 30 items to be analyzed.

Column 5 must contain the alphanumeric code for items that the examinee has omitted. This can be a digit larger than the number of alternatives, a letter, or some other character including a “blank.” For example, it might be “9” for a five-alternative item, an “O” for omitted, or a period. Column 7 must contain the alphanumeric code for items that the examinee did not reach and therefore did not have a chance to answer. Like the omission code, it can be a digit larger than the number of alternatives or any other character. In Figure 2-1, the letter “O” indicates an omitted item, and “N” indicates a not-reached item.

For dichotomously scored items, ITEMAN makes no distinction between items that are omitted and items that are not reached; both are scored as incorrect. For rating-scale-type items, ITEMAN will allow you to specify one of three ways for dealing with missing data (these options are presented on the Options screen). Both the responses recorded as omitted and those recorded as not reached will be considered “missing.”

Columns 9 and 10 contain the number of characters at the beginning of each examinee’s data record used for identification. As with the number of items, these digits must be right justified — the “tens” must be in column 9 and the “units” in column 10. The maximum number of identification characters is 80. If columns 9 and 10 are left blank or if zero identification characters are specified, examinee identification will not be expected and the examinees’ responses must begin in column 1 on the data lines. The example in Figure 2-1 indicates that there are 5 characters of identification for each examinee; in the data lines (beginning on line 5 of the input file in Figure 2-1), you will note that the examinees are identified by “EX001” through “EX005”.

The Keyed Responses The second line of the file contains the keyed response for each item in the data file. The code in column 1 corresponds to the key for item 1 and so forth. The entire key must be contained on a single line. Thus, for the example in Figure 2-1, Item 1 is keyed “1,” Item 2 is keyed “4,” and the last item (Item 30) is keyed “3”. Note also the optional comment on the key line following item 30, which identifies the data on that line.

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Dichotomously Scored Items For dichotomously scored items, each keyed response is coded as the character that will be scored as correct for the item. The key can be specified using the numerals 1 through 9 or the letters A through I. For example, a “1” means that all responses of “1” will be counted as correct. For convenience, “A” and “a” have been defined to be equivalent to “1”. Similarly, “B” = “b” = “2”. This equivalence continues through “I” = “i” = “9”. There is no letter equivalent to zero. Note, however, that ITEMAN distinguishes between alphabetic (e.g., “A”) and numeric (e.g., “1”) keyed responses for purposes of determining how the alternatives for the item will be labeled in the ITEMAN output file. If you want the alternative/option labels to appear as alphabetic then you should provide keyed responses for your items that are alphabetic. (See Figure 2-3.)

Multipoint Items ITEMAN allows you to analyze multipoint as well as dichotomously scored items. Multipoint items are not dichotomously scored. Instead, two or more possible response categories are ordered along some scale. Examples are five-point Likert-type rating scales and the Like/Indifferent/Dislike scales on interest inventories. The response can be specified using the numerals 1 through 9 or the letters A through I. For convenience, “A” and “a” have been defined to be equivalent to “1”. Similarly, “B” = “b” = “2”. This equivalence continues through “I” = “i” = “9”. There is no letter equivalent to zero.

For multipoint items, the permissible values of the key are “+” and “–” (see Figure 2-2). When an item is keyed “+”, the item score is equal to the number of the response (for example, “1” or “A” = 1). When an item is keyed “–”, the item score is equal to the complement of the number of alternatives (for example, “1” or “A” = 5 for a five-alternative item).

The Number of Alternatives The third line of the file must specify the number of alternatives for each item. For dichotomously scored items, this must be equal to the number of choices allowed for the item. In the example in Figure 2-1, each of the items has five alternatives. For multipoint items, the number of alternatives is the maximum value the item response can take. It must be specified by a digit between 2 and 9. In ITEMAN, the number of alternatives is used in computing the response-alternative statistics.

Figure 2-2. Example of a Data File Containing Multipoint Items 30 X Y 10 30 items and 10-character ids +++++---++--++++--+-+++++++--- keys for scale 555555555555555555557777777777 numbers of alternatives 111111111111111111111111111111 scale assignment code EX9013371D214214123242343423111231243767 EX2024438D312214214242443423224562332565 EX1224466W224212331332443124325462437124 EX2036874U22421112X432443323226556664122 EX2034163S324214242342443443226535467343 EX3021364L212213141242444422221323342576 . . .

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The Scale Inclusion Codes The fourth line contains scale inclusion codes, which indicate whether an item should be included in the analysis. Items coded “Y” are included in the analysis; those coded “N” are not. In the example shown in Figure 2-1, all the items will be included in the analysis.

ITEMAN and Multiple Scales When the test to be analyzed by ITEMAN is composed of multiple scales, the items are assigned to the scales using the inclusion codes. Figure 2-3 shows a data file for a test composed of three scales.

Figure 2-3. Example Data File for a Test With Multiple Scales 45 S N 10 ABDABDCACBCDCABCDBDABDCACBCDDBABCADCBDABDBDAD KEY 444444444444444444444444444444444444444444444 N ALTS 000000000000000122112211221122112211221122112 SCALES ID#998783 ABDACBBDDDAACCBDCACDCBCCBCDCDACDACCACBBCBBBAD ID#989367 AADCABBDCDACBBCCBDAABCCCACDBSSSAAACACDBBBDDCN ID#103102 ABDACBADCBAACBBDCACBBDCAAABBDABDCDCBCDCBDDDAA ID#993167 ABDACBADCBDACBBDCACBCDCABCDBDABDCACDCDBBDBCAD ID#983458 CADBDAABADBBBBCAACDDACBBADBDCCAAABBADCCCBANNN . . .

Items on the first scale are assigned inclusion codes of “0”, items on the second scale are assigned inclusion codes of “1”, and so forth. Up to ten scales can be specified using the digits 0 through 9 as inclusion codes. You can still use “N” to exclude items altogether. A “Y” will assign the item to scale zero.

The Examinee Data Lines The examinee response data follow the fourth control line. The data for each examinee must be placed on a single line regardless of the number of items, and each examinee’s identification data must begin in the first column and continue through the number of characters you specified in the first line. Any alphanumeric coding that corresponds to the omitted and not-reached codes in the first control line and to the range of legitimate responses specified in the third control line can be used to indicate the examinees’ responses. In Figure 2-1 and Figure 2-2, the digits 1 through 5 were used for examinee responses. In Figure 2-3, the letters A through D were used.

Comments Comments can be placed to the right of the data on any line. There must be at least one space between the data on any given line and a comment on that line.

Using Files Produced by Optical Scanners Most data files produced by optical scanning devices are very close to the format that ITEMAN requires, with the exception of the four control lines that must be at the beginning of all ITEMAN data files.

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In order for scanned data files to be compatible with ITEMAN you must ensure that the scanner output file is written in an ASCII format with one line for each examinee and that all scanned demographic and identification information (e.g., name, student ID, date of birth, etc.) is located at the beginning of each examinee’s record. You must also ensure that the scanner output file writes each item response in a single character-width field and that, once begun, the item responses are continuous.

To use ITEMAN with a scanner-produced (ASCII) output file you must either append the first four control lines of information to the top of your scan data file, or use the option for running ITEMAN in batch mode and include the four control lines in the header file used for batch operation (see Chapter 3). If you decide to append the four control lines to the top of your scanner data file, the easiest method to accomplish this is to create a small file containing only the four control lines using your text editor (Notepad, Wordpad) and paste it onto the top of the scanner file. Note that if you use a word processor, such as Microsoft Word to create or combine these file, you must save the file as a text (.TXT) file; ITEMAN will not function properly with a .DOC file saved from Word or other word processor.

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Chapter 3: Analyzing Items and Tests

Introduction

This chapter describes how to use the ITEMAN for Windows Item and Test Analysis Program. The program analyzes items and tests composed of from one to ten scales (or subtests). ITEMAN can also be used to compute and record test scores for individual examinees.

ITEMAN will allow you to analyze scales containing either dichotomously scored or multipoint items. Dichotomously scored items are those that can be scored in a binary (0 or 1) fashion. In psychological tests, this usually refers to correct/incorrect scoring. True-false items are, by their nature, dichotomously scored. Most multiple-choice items are scored dichotomously. Multipoint items are not dichotomously scored. Instead, two or more possible response categories are ordered along some scale. Examples are seven-point Likert-type rating scales and Like/Indifferent/Dislike interest-inventory scales. Multipoint items differ from dichotomously scored items in that the item responses are not reduced to one of two possible values.

Running ITEMAN The ITEMAN Interface When you exit the ITEMAN installation program, a new group/folder called “Assessment Systems” will appear in the ProgramManager/Start Menu. Select the ITEMAN for Windows icon within the folder to start the program. The ITEMAN copyright screen will appear briefly.

Five pull-down menus and three buttons are immediately available (see Figure 3-1 and Figure 3-2). The File menu contains the commands for printing and exiting the program. The Edit menu permits access to the ITEMAN file browser/editor, with which you can browse any of the ASCII files ITEMAN uses and edit the input file. The Configure menu opens the Analysis Options Configuration Window, also accessible by clicking on the pencil icon button below the menus. ITEMAN performs the analysis when you select Go under the Analyze menu or click on the computer button. The Help menu accesses copyright information about ITEMAN.

Figure 3-1. The Three Initial Buttons and Their Commands

Configure Analyze Exit

Entering File Names When you access the Analysis Options Configuration Window (see Figure 3-3), it is ready to accept file names for the input and output files. Type the name in the space provided or

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click the folder icon to select an existing file without typing. You may also double click in the space provided or press the space bar. Three sets of radio buttons allow you to specify whether you want ITEMAN to create a score file or external statistics file or to use an exceptions file. If you select Yes for any of these, a folder icon appears, allowing selection or creation of a file.

Figure 3-2. Main ITEMAN Program Window

The Input File The input file contains the test data that you want to analyze. Input data can be produced from an optical scanner (optical mark reader) or might have been entered into a data file by some other means. The program will automatically attach the .DAT extension to the filename that you enter unless you explicitly specify a different extension. Therefore, if your input file has an extension other than .DAT (e.g., DATA.TST), you must enter the full file name, including the extension, or ITEMAN will not be able to locate it.

The Output File After specifying the name of your input file you must enter a name for the output file to which the results of the analysis will be written. The .OUT file extension will be attached to this filename unless you explicitly specify another extension. If a file with the name you specify for your output already exists, the program will display the prompt shown in Figure 3-4. If the old output file is valuable and you do not want to overwrite it, select No. You can then enter a different name for the output file. If you want to erase the existing file of that name, select Yes.

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Figure 3-3. ITEMAN Configuration Window (File Names)

Examinee Scores Option If you want ITEMAN to compute and retain the scores for the examinees, select the Yes radio button in the “Generate Examinee Scores” box. A folder icon will appear, allowing you to specify the file name as described above. If a file by that name already exists, the program will ask whether you want to erase and replace the old file. A file extension of .SCR will be applied to the file name you provide unless you provide another extension as part of the file name. You can browse the scores by selecting Score File under the Edit menu after completing the analysis.

Figure 3-4. Overwrite File Confirmation Box

Key Alternative Exceptions Option The exceptions file capability in ITEMAN allows you to re-analyze data in cases where, in a multiple-choice test, you might find that you want to consider more than one option/alternative as the correct (keyed) response. Some possible situations for giving credit to more than one alternative include poorly phrased questions, conflicting source information, or an indication of additional problems from a previous ITEMAN analysis. At the extreme, all responses/alternatives can be scored as correct. As a result, no single

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response will be considered correct and the item will have no influence on the total score. For whatever reason, ITEMAN allows you to analyze a data file which contains such “exceptions.” If you need to use the exceptions capability, you must first create an “exceptions” file. The exceptions file is an ASCII (text) file that contains the following information:

Line 1: The header line must start with ITEMAN3.5 (beginning in column 1), which must be in capital letters.

Line 2 (and following): The Item Sequence Number (from the input file) followed by at least one space and then the numerical value(s) of any alternative(s) that you want to have considered as correct, each separated by one space. The alternatives must be declared as numerical values (A=1, B=2, C=3, D=4, and so on). An attempt to read alphabetic characters in the exceptions file will result in an error.

You can create an exceptions file by either using a text editor such as NOTEPAD or WORDPAD or a word processor(such as Microsoft Word) that can save a file as an ASCII (text) file with line breaks.

The data for the alternatives defined as “exceptions” will then be combined with the data from the keyed response for purposes of the item analysis. The alternative(s) that you declared in the exceptions file will be denoted by an ‘E’ under the “Key” column header in the analysis output file.

An example of an ITEMAN exceptions file for the SAMPLE1.DAT data file is found in the file SAMPLE1.EXP on your original ITEMAN Program Diskette. A listing of the SAMPLE1.EXP exceptions file is shown in Figure 3-5.

Figure 3-5. Sample Exceptions File SAMPLE1.EXP ITEMAN3.5 Exceptions File 2 4 6 1 2 3 4 20 1 2

In this example exceptions file, alternative 4 in item 2 is defined as an exception to be counted as correct. For Item 6, alternatives 1, 2, 3, and 4 will all be counted as correct. For item 20 the alternatives numbered 1 and 2 are defined as correct (note that although option 2 is the “keyed” response, this has no effect on the operation of the exceptions file).

If you want ITEMAN to read exception information from a file, click on the Yes radio button in the Exceptions File box and select the exceptions file by clicking on the folder icon. ITEMAN expects .EXP files by default. If your exceptions file has a different extension, you must specify it rather than simply clicking on the appropriate file name.

External Statistics Option The external statistics file is for use when you want to save the results of the analysis as an external ASCII (text) file for analysis with another statistical program. The exact format of the file that is produced is specified, in detail, in Appendix A. You may browse this file by selecting Statistics File under the Edit menu after completing the analysis.

If you want to have ITEMAN save the statistics to an ASCII file, click on the Yes radio button in the External Statistics box. ITEMAN will then ask you to enter a file name for the

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statistics file. Again, if a file with that name already exists, the program will ask whether or not you want to erase and replace the old file. If you respond No, you will be asked to enter a different filename. A file extension of .STT will be applied to the file name you provide unless you specifically enter another extension.

Entering Analysis Options After entering the appropriate file names, click on the Options button or tab to access that screen (Figure 3-6). There are a number of options that you may set to your preferences for the ITEMAN analysis. The defaults for the program configuration are read from the file ITEMAN.CFG when the program begins. (The format of that file, which can be modified, is described below.) Options can be toggled either with the mouse or the keyboard. To toggle options with the keyboard, use the Tab key to highlight the next option and an arrow key to toggle it.

Figure 3-6. ITEMAN Configuration Window (Options)

Type of Correlations This option allows you to define the type of item-total score correlation that you want ITEMAN to compute and report for dichotomous scales (note that multipoint scales always use product-moment correlations). You can select either a point-biserial correlation or a biserial correlation. The point-biserial correlation is a Pearson product-moment correlation between the 0-1 item scores and the number-correct (total) score for that test (scale). Most item analysis work will use the point-biserial correlation as the preferred method and it should probably be selected if you do not understand the distinction between the two types of correlations. The biserial correlation is a correlation between dichotomized item scores

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(based on the assumption that the dichotomous item score—correct vs. incorrect—has an underlying normal distribution) and the number-correct (total) score. It should be noted that biserial correlations, since they are not product-moment correlations, can exceed 1.0.

Ability Grouping This option allows ITEMAN to group the examinees into the highest and lowest 27% based on the number-correct (total) scores for each scale (test). When this option is selected, the proportion/percentage endorsements for the high and low score (ability) groups are reported in addition to the total (entire) group. It should be noted, however, that in order to perform the ability grouping based on number-correct scores, ITEMAN requires a second “pass” through the data file and thus will take somewhat longer to complete the analysis than when ability grouping is not selected.

When ability grouping is in effect the classical index of discrimination is automatically computed for each item in dichotomous test scales. The classical index of discrimination measures how well the item can differentiate between high scoring and low scoring examinees. Items that do not differentiate well between high and low scoring examinees might not be providing useful psychometric information. The index is the difference between the proportion correct in the high ability (score) group and the low ability (score) group (Crocker & Algina, 1986). This index has a possible range of -1.0 to +1.0, but negative values and low (e.g., less than 0.20) values might be indicative of poor item performance. In most cases the classical index of discrimination will identify the same “poor” performing items as does the item-total correlation (point-biserial or biserial).

Subgroup Analysis This option tells ITEMAN whether to perform the analysis on a subset of the data file. If you select Yes, a button with a pencil icon appears, which accesses the subgroup analysis window. The subgroup target code can be up to 4 characters in length and specifies the code in the examinee’s identification field that you want to include in the subgroup analysis. You will also be required to enter the beginning column and ending column for the code (which will be the same for a single-character target code). For example, Figure 3-7 shows a subgroup analysis of cases with a “target” code of “F” in column 6 of the data file.

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Figure 3-7. Subgroup Analysis Window

Spuriousness Correction This option allows you to implement a correction on the item-total score correlations to remove the influence of each item being included in the total score. The inclusion of an item in the total (number-correct) score will have a larger effect on item-total correlations for short tests, but its impact diminishes as test length increases. The correction is computed based on formulas provided by Guilford (1963).

Endorsements Endorsement rates can be expressed as either proportions or percentages, depending on your preferences.

Score Distribution/Histogram Interval Width This option allows you to specify the width of the score intervals to be used in the score distribution/histogram output that is provided for each dichotomous test scale. Specifying a score interval width of “1” will result in an ungrouped score frequency distribution and is recommended for short tests. Interval widths larger than “1” will result in score intervals of the width specified. Note that ITEMAN will automatically “clip off” score intervals at the bottom and top of the distribution if there are no examinees in those intervals. If this happens the score distribution will show this by printing the statement “No examinees below (above) this score.”

Once you have selected the program configuration options that you would like to have in effect for the analysis, click on the OK button (or Cancel button to make ITEMAN ignore the changes you have made).

Default Configuration Options The default configuration options for ITEMAN are read from the ITEMAN.CFG file each time the program is executed. This configuration file enables you to customize your ITEMAN program by defining your own preferences, thus avoiding the re-entry of configuration information each time you run the program. The format of the ITEMAN.CFG file is as follows:

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Line 1: Header Line — can contain any identifying information Line 2: P for point-biserial correlations, B for biserial correlations Line 3: Y for ability grouping Line 4: Y for subgroup analysis Line 5: Y to correct correlations for spuriousness Line 6: P to express endorsements as proportions, C to express endorsements as

percentages Line 7: Integer specifying width of score intervals on distributions (remember “1”

means no score grouping) Lines 8 through 10 are optional (invoked only if Line 4 is “Y”): Line 8: Subgroup analysis target code (up to 4 characters). Line 9: Beginning column of subgroup analysis target code. Line 10: Ending column of subgroup analysis target code.

You should examine the ITEMAN.CFG file that came with ITEMAN (see Figure 3-8) to see how this file is constructed. You can create or modify the ITEMAN.CFG file using either a text editor (such as the DOS EDIT program) or by using a word processor and saving the file as a text file with line breaks.

Figure 3-8. Sample Configuration File ITEMAN.CFG **** ITEMAN Version 3.5 Configuration File **** P - Type of Correlation: P = Pt.Biserial B = Biserial Y - Ability Grouping: Y = Yes N = No N - SubGroup Analysis: Y = Yes N = No N - Correct Correlations for Spuriousness: Y = Yes N = No P - Express Endorsements as: P = Proportions C = Percentages 1 - Score Distribution Interval Width (1-3 digit integer)

Missing Data Options If all the data in your file are from dichotomously scored items, the analysis will begin when you click on the computer icon and all missing data will be scored as incorrect and reported in the “other” alternative statistics. When analyzing data that contains multipoint (e.g., Likert) scales, however, an additional window will appear (see Figure 3-9) which will ask you to toggle the type of missing data option that you want to use for the analysis. The missing data option that you select will affect the scores printed for all test scales that are composed of multipoint items. ITEMAN offers three choices for how missing data is handled in multipoint scales: itemwise deletion, scalewise deletion, or casewise deletion.

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Figure 3-9. Missing Data Options

Itemwise Deletion When itemwise deletion is selected, ITEMAN will compute statistics for each item using all the available data and will compute scores for each examinee using data from those items to which the examinee responded. Item statistics, therefore, might be based on varying numbers of examinees within a single scale.

Scalewise Deletion When scalewise deletion is selected, item statistics are based on the set of examinees who had a complete set of valid responses to all items in the scale. Thus the number of examinees responding to each item will be constant within a scale but might vary across scales. For scoring purposes, an examinee with missing data on a particular (multipoint) scale is excluded from the analysis of that scale and a score of -9.00 is recorded for the examinee in the score file (if a score output file was specified.).

Casewise Deletion When casewise deletion is selected, an examinee with missing data on any multipoint scale is deleted from all analyses, not just those involving the multipoint scales. This will result in item statistics where the number of examinees is consistent not only within a scale but across all scales in the analysis. For scoring purposes, a score of -9.00 is recorded in the examinee score file (if score output is selected) for all scales (including any containing dichotomously scored items). Casewise deletion is the only missing data option that will affect the analysis of dichotomously scored items included in the same data file.

Type of Scores in Multipoint Scales Multipoint (e.g., Likert/survey) scale scores are reported as an average of the endorsements across items in the scale. For example, suppose you have a multipoint scale with 5 categories: (1) dislike very much, (2) dislike, (3) neutral, (4) like, and (5) like very much. An individual with an average score of 3.4 is most similar to the characteristics defined by the

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“3” (or neutral) category. Although this approach is preferable for many psychological as well as other survey situations, a summed (total) score has been implemented as an optional feature. Following entry of the multipoint missing data option, another box (Figure 3-10) will appear allowing you to indicate the type of multipoint scores that ITEMAN should compute (averaged or summed).

Figure 3-10. Multipoint Score Type Selection Box

Analysis Once you have selected your file names and analysis options, click on the computer icon (or select Go under the Analyze menu) to start the analysis. Once the analysis has begun, a small window will appear displaying a percentage-complete bar. As the bar fills, the ITEMAN program reads the data file and computes all the requested item and test statistics. The duration of the analysis depends on the speed of the computer you are using, the size of the data set that you are analyzing, and the options you select in the configuration window (ability grouping will require more time). All things considered, ITEMAN is a quickly executing program on most computers for most data sets; most analyses are completed in a few seconds. When the analysis is complete, Figure 3-11 will be displayed.

Browsing Analysis Results You can browse through the output file at the conclusion of the analysis—as well as any of the other files you specified in the ITEMAN configuration window. Choose the appropriate selection under the Edit menu to open the ITEMAN data file editor. Two menus are available in the ITEMAN editor. The File menu allows access to file manipulation and printing commands, and lets you exit the editor, while the Edit menu provides find and replace functions.

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Figure 3-11. Analysis Completed Screen

Printing Analysis Results You can print the output by clicking on the printer icon, by selecting Print from the File menu, or by pressing Alt-P. Any of the files used by ITEMAN for Windows can be printed by first opening them via the Edit menu and then selecting Print under the File menu (or by pressing Alt-P).

Figure 3-12. Output Control Buttons and Their Commands

Print Output View Output

Running ITEMAN in Batch Mode Due to limitations placed on programs by Windows, the Windows version of ITEMAN cannot itself run in batch mode. This can be useful when running ITEMAN overnight with large datasets so your computer is available during the day. Therefore, we have included the DOS Extended version of ITEMAN with your purchase. The algorithms the Windows version uses are identical to those used by the DOS version, as is its output.

The DOS version of ITEMAN can be run in batch mode from a header file. A header file is a file that contains all the information that is normally entered through the keyboard at the time ITEMAN is run. To run the program in a DOS windows from a header file, add the name of the header file after the command ITEMAN: ITEMAN headerfilename

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The header file is an ASCII file either eight or 12 lines long. The first eight lines primarily contain information normally entered from the keyboard. The four optional lines contain the key, number of alternatives, and other information normally contained on the first four lines of the data file for ITEMAN. The required lines in the header file are described below. See Figure 3-13 for an example header file.

1. The name ITEMAN3.5 in all capital letters. This is to ensure that you do not use a header file intended for one of the other analysis programs in the Item and Test Analysis Package for ITEMAN.

2. The name of the input file. 3. The name of the output file (including file extension). Note: Unlike running in the

interactive mode, ITEMAN will not ask if it is okay to write over an existing file with this name— it will just do it.

4. The name of the score file into which you want examinee scores written. If you leave this line blank, ITEMAN will not compute scores.

5. The name of the Key Exceptions file. If you leave this line blank, ITEMAN assumes there are no exceptions in the analysis.

6. The name of the external statistics file. If you leave this line blank, ITEMAN will not create an external statistics file.

7. The missing data option. Note that although this is used only if the analyses include multipoint items, some numerical value (1, 2, or 3) must be included on this line for batch mode to work properly. The missing data option must be a single digit (1, 2, or 3) corresponding to the options that ITEMAN normally prompts you for in that window. “1” is for itemwise deletion, “2” for scalewise deletion, and “3” for casewise deletion.

8. Enter “Y” if multipoint scores are to be averaged across items, “N” if multipoint scores should be summed (totals) across items.

Figure 3-13. Example Header File for Batch Mode ITEMAN3.5 math24.dat math24.out math24.scr math24.exp math24.stt 2 Y 30 o n 0 423142242113424141324213411334 444444444444444444444444444444 YYYYYYYYYYYYYYYYYYYYYYYYYYYYYY

The four optional lines consist of the information that normally constitutes the first four lines of an ITEMAN input file (see Chapter 2). If they are not included in the header file, ITEMAN will assume that this information is in the first four lines of the input file. If they are included in the header file, ITEMAN will assume that the input file does not contain this information. When using a header file, it is very important that the four lines of information occur in only one place. If they are included in both the input file and the header file, they will be analyzed as data in the input file.

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Interpreting the Analyses The first page of the analysis output file contains summary information about the analysis, including file names and configuration options that were in effect. This summary “header” page can prove useful if you must, at some point in the future, re-run an analysis on the same data. The actual results of the item and test analyses performed by ITEMAN are then printed in four sections: item statistics for dichotomously scored items (if any), item statistics for multipoint items (if any), summary statistics for each scale, and score frequency distributions for dichotomously scored scales (if any). The four sections will appear in the above order in the output following the analysis summary “header” page.

Item Statistics for Dichotomously Scored Items For scales composed of dichotomously scored items, the following statistics are output for each item included in the analysis (values that cannot be computed will print as blanks). An example of the item and response-alternative output of ITEMAN is shown in Figure 3-14. This example uses the ability grouping configuration option.

Seq. No. This is the item’s sequence number within the data file.

Scale-Item. This is the scale number to which the item was assigned and the item’s sequence number within the scale. Scale numbering begins at 0.

Proportion/Percentage Correct. This is the proportion or percentage (depending on your configuration option) of examinees who answered the item correctly. Extreme values (close to 0.0 or close to 1.0) indicate that the item was too difficult or too easy for the examinees.

Disc. Index. This is the classical index of item discrimination that provides information about the item’s ability to differentiate between high and low scoring examinees. The index of discrimination is computed as:

Disc. Index = PHigh - PLow

Where PHigh is the proportion of examinees in the upper 27% of the score distribution who answered the item with the correct/keyed answer and PLow is the same proportion in the lower 27% group.

Item-Total Correlation.

Biser. This is the biserial correlation between correct responses to the item and number-correct scores on the scale to which the item was assigned. A positive value indicates that examinees who answered the item correctly scored relatively high on the scale as a whole. A negative value indicates that examinees who answered correctly scored relatively low on the scale as a whole. A negative biserial correlation is undesirable for the keyed response alternative but desirable for the other alternatives.

Point-Biser. This is the point-biserial correlation between correct responses on the item and the total scale scores.

The alternative statistics give much of the same information as the item statistics. The difference is that these statistics are calculated separately for each response alternative and are thus based on endorsement of that alternative rather than on selection of the correct or

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keyed response. An asterisk appear to the right of the data for the alternative keyed as correct.

Because the example in Figure 3-14 uses ability grouping the proportion/percentage endorsing each alternative (response) is provided for the total group, the low ability (lowest 27% scoring) group, and the high ability (upper 27% scoring) group.

Figure 3-14. Item and Alternative Statistics for Dichotomously Scored Items Item Statistics Alternative Statistics ----------------------- ----------------------------------- Seq. Scale Prop. Disc. Point Prop. Endorsing Point No. -Item Correct Index Biser. Alt. Total Low High Biser. Key ---- ----- ------- ------ ------ ----- ----- ---- ---- ------ --- 1 1-1 .58 .63 .37 1 .16 .33 .10 -.45 2 .58 .22 .85 .37 * 3 .08 .06 .00 -.16 4 .18 .39 .05 -.50 Other .00 .00 .00 2 1-2 .38 .53 .38 1 .26 .44 .10 -.50 2 .14 .06 .00 -.21 3 .38 .17 .70 .38 * 4 .22 .33 .20 -.39 Other .00 .00 .00 3 1-3 .20 .04 -.13 1 .24 .44 .15 -.49 2 .20 .11 .15 -.13 * CHECK THE KEY 3 .16 .22 .15 -.28 2 was specified, 4 works better 4 .40 .22 .55 .15 ? Other .00 .00 .00

As mentioned above, when a statistic cannot be calculated for the response alternative the value will not be printed. This occurs most frequently when no examinees endorse an alternative.

Item Statistics for Multipoint Items For scales composed of multipoint items, the following statistics are output for each item included in the analysis (blanks will be printed for any value that cannot be computed). An example of this type of output is shown in Figure 3-15.

Seq. No. This is the item’s sequence number within the data file.

Scale-Item. This is the scale number to which the item was assigned and the item’s sequence number within the scale. Scale numbering begins at 0

Item Mean. This is the average response to the item. It will be computed somewhat differently depending upon the missing data option selected. For scalewise deletion, the average for each item in a scale will be based on the same set of examinees (those with complete data on that scale). For casewise deletion, the average will be based on those examinees with complete data on all multipoint scales. For itemwise deletion, the average migh be based upon different subsets of examinees for each item.

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Figure 3-15. Item and Response Alternative Statistics for Mutipoint Items Item Statistics Alternative Statistics --------------------------------- ----------------------- Seq. Scale Item Item Item-Scale N per Alter- Proportion No. -Item Mean Var. Correlation Item native Endorsing Key ---- ----- ------ ------ ----------- ----- ------ ---------- --- 21 3-1 4.120 4.746 .89 50 1 .20 + 2 .10 3 .10 4 .12 5 .12 6 .18 7 .18 Other .00 22 3-2 4.125 2.401 .81 48 1 .08 + 2 .04 3 .23 4 .17 5 .35 6 .04 7 .08 Other .04 23 3-3 3.918 3.299 .75 49 1 .02 + 2 .31 3 .20 4 .04 5 .14 6 .20 7 .08 Other .02

Item Var. This is the variance of the responses to the item. Its computation can also be affected by the missing data option selected.

Item-Scale Correlation. This is the Pearson product-moment correlation between responses to the item and average scores for examinees.

N per Item. This is the number of examinees on which the item statistics are based.

The alternative statistics for multipoint items describe the proportion/percentage (depending on your configuration) of examinees endorsing each response within the specified range for the item. In the column labeled “Key,” a plus or minus sign indicates the direction in which the multipoint item was scored when examinee scores and other statistics were computed.

Once again, a blank value field indicates that the statistic could not be calculated for the response alternative.

Scale (Test) Statistics The following statistics are provided by ITEMAN for each scale (subtest) analyzed (see Figure 3-16).

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N of Items. This is the number of items in the scale that are included in the analysis. For scales composed of dichotomously scored items, this will be the total number of items on the scale.

N of Examinees. This is the number of examinees that are included in the analysis for the scale. For scales composed of dichotomously scored items, this will be the total number of examinees in the data file; it will also be the total number of examinees for multipoint scales in the same data file unless the casewise deletion option was selected for these scales.

For scales containing multipoint items, the number of examinees can differ as a result of the missing data option selected. When itemwise deletion is selected, the number printed is the total number of examinees in the data file; the actual number used to compute the item statistics can vary from item to item. When scalewise deletion is selected, the number will be the total number of examinees with complete data for that scale. When casewise deletion is selected, the number will be the total number of examinees with complete data on all the multipoint scales.

Mean. For scales with dichotomously scored items, this is the average number of items on each scale that were answered correctly. For scales with multipoint items, it is the average examinee score for examinees included in the analysis. An examinee’s score can be his or her average response or the sum of the weights for their responses. When itemwise deletion of missing data is selected, each examinee’s score can be based on a different subset of items.

Variance. This is the variance of the distribution of examinee scores on each scale. It gives an indication of the spread of the scores around the mean score and, for multipoint items, can be affected by the missing data option selected.

Std. Dev. This is the standard deviation of the distribution of examinee scores for each scale. It is the square root of the variance.

Skew. This is the skewness of the distribution of examinee scores for each scale. The skewness gives an indication of the shape of the score distribution. A negative skewness indicates that there is a relative abundance of scores at the high end of the scale distribution. A positive skewness means that there is a relative abundance of scores at the low end of the distribution. A skewness of zero means that the scores are symmetrically distributed about the mean.

Kurtosis. This is the kurtosis of the distribution of examinee scores for each scale. The kurtosis indicates the peakedness/flatness of the distribution relative to that of a normal distribution. A positive value indicates a more peaked distribution; a negative value indicates a flatter distribution. The kurtosis of a normal distribution is zero.

Minimum. This is the lowest score on each scale for any examinee.

Maximum. This is the highest score on each scale for any examinee.

Median. This is the examinee score at the fiftieth percentile for each scale. It is thus the score that half of the examinees scored at or below. Interpolation is not used in the calculation of this value.

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Figure 3-16. Scale Summary Statistics Missing-data option: Compute statistics on all available item responses There were 50 examinees in the data file. Scale Statistics ---------------- Scale: 1 2 3 ------- ------- ------- N of Items 10 10 10 N of Examinees 50 50 50 Mean 4.800 7.180 3.935 Variance 5.160 6.988 2.145 Std. Dev. 2.272 2.643 1.465 Skew 0.217 -0.909 0.057 Kurtosis -0.981 0.018 -1.423 Minimum 1.000 0.000 1.667 Maximum 9.000 10.000 6.333 Median 5.000 8.000 4.100 Alpha 0.636 0.821 0.943 SEM 1.370 1.120 0.351 Mean P 0.480 0.718 N/A Mean Item-Tot. 0.301 0.509 0.809 Mean Biserial 0.387 0.679 N/A Max Score (Low) 3 6 N/A N (Low Group) 18 16 N/A Min Score (High) 6 9 N/A N (High Group) 20 19 N/A Scale Intercorrelations ----------------------- 1 2 3 1 1.000 0.712 0.109 2 0.712 1.000 0.146 3 0.109 0.146 1.000 Alpha. This is the alpha reliability coefficient for each scale (Crocker & Algina, 1984). It is

an index of the homogeneity of each scale. It can range in value from 0.0 to 1.0. This statistic is only appropriate for non-speeded scales designed to measure a single trait. The alpha value is usually considered to be a lower-bound estimate of the reliability of a scale.

SEM. This is the standard error of measurement for each scale. It is an estimate of the standard deviation of the errors of measurement in the scale scores. It is computed by the formula SEM = S 1− rxx where S is the scale standard deviation and rxx is the alpha reliability.

Mean P. For scales composed of dichotomously scored items, this is the average proportion correct across all items on the scale. This statistic is not applicable (N/A) for scales composed of multipoint items.

Mean Item-Tot. For scales composed of dichotomously scored items, this is the average point-biserial correlation across all the items in the scale. For scales composed of multipoint items, this is the mean Pearson correlation between item responses and scale

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scores for items in the scale. Only those items for which the correlation could be computed are included in the average.

Mean Biserial. For scales containing dichotomously scored items, this is the average biserial correlation across all of the items on the scale. This statistic is not applicable (N/A) for scales composed of multipoint items.

Max Score (Low). When ability grouping is selected from the configuration options, this is the maximum score an examinee could attain on the scale and still be considered a member of the low ability (score) group.

N (Low). When ability grouping is selected, this is the number of examinees in the lowest score grouping. Ideally this number would represent exactly 27% of the total number of examinees for the scale (test). The score that defines the maximum score for membership in the low ability group (above) is selected based on that score interval containing the 27th percentile. Depending on the numbers of examinees at that score point, however, the actual percentage of examinees in the lower ability (score) group can, therefore, be slightly larger than the target 27%.

Min Score (High). When ability grouping is selected from the configuration options, this is the minimum score an examinee could attain on the scale and still be considered a member of the high (upper) ability (scoring) group.

N (High). When ability grouping is selected, this is the number of examinees in the highest score grouping. Ideally this number would represent exactly 27% of the total number of examinees for the scale (test). The score that defines the minimum score for membership in the high ability group is selected based on that score interval containing the 73rd percentile. Depending on the numbers of examinees at that score point, however, the actual percentage of examinees in the high (upper) ability (score) group can, therefore, be slightly larger than the target 27%.

Scale Intercorrelations. These are the Pearson product-moment correlations among the examinee scores on the individual scales. When some or all of the scales contain multipoint items, the intercorrelations can be affected by the missing data option selected. When itemwise deletion is selected, the correlations will be based on all examinees in the data file; however, each examinee’s score might be based on a different subset of items. When scalewise deletion is selected, the correlation between any two scales will be based on the subset of examinees having scores computed on both scales. When casewise deletion is selected, the correlations will be based on the subset of examinees who have complete data on all the multipoint scales.

Score Distribution Table The score distribution table for Scale 1 in the output file from the SAMPLE2.DAT input file included with your ITEMAN installation is shown in Figure 3-17. One table for each scale of dichotomous items is provided in the output file. It contains the following columns:

Number Correct. The number of items responded to correctly in each row.

Frequency. The number of examinees correctly answering the number correct in a given row.

Cum Freq. The accumulation of the Frequency column.

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PR. The percentile rank for a given row.

PCT. The percent of the examinees obtaining a certain row’s number correct. This figure is rounded, so the column might not sum to exactly 100 percent. The percentage is also shown in graphical format in the last column. Each pound sign (#) signifies one percent of the examinees.

Figure 3-17. The Score Distribution Table from SAMPLE2.DAT SCALE # 1 Score Distribution Table Number Freq- Cum Correct uency Freq PR PCT ------- ------- ------ ---- ---- 1 2 2 4 4 |#### 2 8 10 20 16 |################ 3 8 18 36 16 |################ 4 5 23 46 10 |########## 5 7 30 60 14 +############## 6 8 38 76 16 |################ 7 5 43 86 10 |########## 8 3 46 92 6 |###### 9 4 50 99 8 |######## 10 0 50 99 0 + |----+----+----+----+----+ 5 10 15 20 25 Percentage of Examinees

Optional Score Output Figure 3-18 shows an example of the optional examinee score output file provided by ITEMAN. For scales of dichotomously scored items, number-correct scores will be in the data file. For scales composed of multipoint items, either the average or summed item score (depending on your selection) will be provided for each examinee. The first line contains the number of characters used to identify the examinees, the number of scales to which items were assigned, and the name of the input file. The score output then lists the identifying information for all examinees and their scores for each of the scales. The scores will always be listed in sequential order based on the scale labels from 0 through 9. If, for example, the test is composed of three scales labeled 8, 3, and 5, the examinee score output will list the scores in the order: 3, 5, 8. No blank spaces will be left for the other scales.

The missing data option you select will affect the scores output for scales composed of multipoint items. When itemwise deletion is selected, an examinee’s scale score is based on the available item responses. When scalewise deletion is selected, an examinee with missing data on a particular scale is excluded from the analysis of that scale and a score of -9.00 is recorded in the score file. When casewise deletion is selected, an examinee with missing data on any multipoint scale is deleted and a score of -9.00 is recorded in the score file for all scales (including any containing dichotomously scored items).

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Figure 3-18. Sample Examinee Score Output 10 3 Scores for examinees from file C:\ITEMANW\SAMPLE2.DAT EX9013371D 4.00 7.00 2.00 EX2024438D 5.00 10.00 3.30 EX1224466W 4.00 6.00 4.80 EX2036874U 4.00 8.00 5.70 EX2034163S 5.00 9.00 5.00 EX3021364L 6.00 8.00 2.40 EX2041546B 7.00 7.00 2.40

References Guilford, J. P. (1963). Psychometric methods. (2nd ed.) New York: McGraw-Hill.

Crocker, L., and Algina, J. (1986) Introduction to classical and modern test theory. New York: Holt, Rinehart and Winston.

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Appendix A

File Layout for the ITEMAN External Statistics File Dichotomous Item Scales Field Contents Columns Field Type Item Sequence Number 1 - 3 I3 ( XXX ) Scale Number 5 I1 ( X ) Scale Sequence Number 7 - 9 I3 ( XXX ) Keyed Response 11 I1 ( X ) Number of Alternatives 13 I1 ( X ) Number of Examinees (Attempting Item) 15 - 19 I5 ( XXXXX ) Discrimination Index 21 - 26 F6.3 ( XX.XXX ) Keyed Response Block Total Grp Prop/Pct Correct 28 - 34 F7.3 ( XXX.XXX ) Low Grp Prop/Pct Correct 36 - 42 F7.3 ( XXX.XXX ) Top Grp Prop/Pct Correct 44 - 50 F7.3 ( XXX.XXX ) Point-Biserial (r) 52 - 57 F6.3 ( XX.XXX ) Biserial (r) 59 - 64 F6.3 ( XX.XXX ) Alternative 1 (A) Response Block Total Grp Prop/Pct Correct 66 - 72 F7.3 ( XXX.XXX ) Low Grp Prop/Pct Correct 74 - 80 F7.3 ( XXX.XXX ) Top Grp Prop/Pct Correct 82 - 88 F7.3 ( XXX.XXX ) Point-Biserial (r) 90 - 95 F6.3 ( XX.XXX ) Biserial (r) 97 - 102 F6.3 ( XX.XXX ) Alternative 2 (B) Response Block Total Grp Prop/Pct Correct 104 - 110 F7.3 ( XXX.XXX ) Low Grp Prop/Pct Correct 112 - 118 F7.3 ( XXX.XXX ) Top Grp Prop/Pct Correct 120 - 126 F7.3 ( XXX.XXX ) Point-Biserial (r) 128 - 133 F6.3 ( XX.XXX ) Biserial (r) 135 - 140 F6.3 ( XX.XXX )

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Dichotomous Item Scales (Continued) Field Contents Columns Field Type

Alternative 3 (C) Response Block Total Grp Prop/Pct Correct 142 - 148 F7.3 ( XXX.XXX ) Low Grp Prop/Pct Correct 150 - 156 F7.3 ( XXX.XXX ) Top Grp Prop/Pct Correct 158 - 164 F7.3 ( XXX.XXX ) Point-Biserial (r) 166 - 171 F6.3 ( XX.XXX ) Biserial (r) 173 - 178 F6.3 ( XX.XXX ) Alternative 4 (D) Response Block Total Grp Prop/Pct Correct 180 - 186 F7.3 ( XXX.XXX ) Low Grp Prop/Pct Correct 188 - 194 F7.3 ( XXX.XXX ) Top Grp Prop/Pct Correct 196 - 202 F7.3 ( XXX.XXX ) Point-Biserial (r) 204 - 209 F6.3 ( XX.XXX ) Biserial (r) 211 - 216 F6.3 ( XX.XXX ) Alternative 5 (E) Response Block Total Grp Prop/Pct Correct 218 - 224 F7.3 ( XXX.XXX ) Low Grp Prop/Pct Correct 226 - 232 F7.3 ( XXX.XXX ) Top Grp Prop/Pct Correct 234 - 240 F7.3 ( XXX.XXX ) Point-Biserial (r) 242 - 247 F6.3 ( XX.XXX ) Biserial (r) 249 - 254 F6.3 ( XX.XXX ) Alternative 6 (F) Response Block Total Grp Prop/Pct Correct 256 - 262 F7.3 ( XXX.XXX ) Low Grp Prop/Pct Correct 264 - 270 F7.3 ( XXX.XXX ) Top Grp Prop/Pct Correct 272 - 278 F7.3 ( XXX.XXX ) Point-Biserial (r) 280 - 285 F6.3 ( XX.XXX ) Biserial (r) 287 - 292 F6.3 ( XX.XXX ) Alternative 7 (G) Response Block Total Grp Prop/Pct Correct 294 - 300 F7.3 ( XXX.XXX ) Low Grp Prop/Pct Correct 302 - 308 F7.3 ( XXX.XXX ) Top Grp Prop/Pct Correct 310 - 316 F7.3 ( XXX.XXX ) Point-Biserial (r) 318 - 323 F6.3 ( XX.XXX ) Biserial (r) 325 - 330 F6.3 ( XX.XXX )

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Dichotomous Item Scales (Continued) Field Contents Columns Field Type

Alternative 8 (H) Response Block Total Grp Prop/Pct Correct 332 - 338 F7.3 ( XXX.XXX ) Low Grp Prop/Pct Correct 340 - 346 F7.3 ( XXX.XXX ) Top Grp Prop/Pct Correct 348 - 354 F7.3 ( XXX.XXX ) Point-Biserial (r) 356 - 361 F6.3 ( XX.XXX ) Biserial (r) 363 - 368 F6.3 ( XX.XXX ) Alternative 9 (I) Response Block Total Grp Prop/Pct Correct 370 - 376 F7.3 ( XXX.XXX ) Low Grp Prop/Pct Correct 378 - 384 F7.3 ( XXX.XXX ) Top Grp Prop/Pct Correct 386 - 392 F7.3 ( XXX.XXX ) Point-Biserial (r) 394 - 399 F6.3 ( XX.XXX ) Biserial (r) 401 - 406 F6.3 ( XX.XXX ) Other Response Block Total Grp Prop/Pct Correct 408 - 414 F7.3 ( XXX.XXX ) Low Grp Prop/Pct Correct 416 - 422 F7.3 ( XXX.XXX ) Top Grp Prop/Pct Correct 424 - 430 F7.3 ( XXX.XXX ) Point-Biserial (r) 432 - 437 F6.3 ( XX.XXX ) Biserial (r) 439 - 454 F6.3 ( XX.XXX )

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Multipoint Item Scales Field Contents Columns Field Type Item Sequence Number 1 - 3 I3 ( XXX ) Scale Number 5 I1 ( X ) Scale Sequence Number 7 - 9 I3 ( XXX ) Keyed Response 11 A1 ( + OR - ) Number of Categories (Alternatives) 13 I1 ( X ) Number of Examinees (Attempting Item) 15 - 19 I5 ( XXXXX ) (Blank) 21 - 26 A6 ( XXXXXX ) Keyed Response Block Item Mean 28 - 34 F7.3 ( XXX.XXX ) Item Variance 36 - 42 F7.3 ( XXX.XXX ) (Blank) 44 - 50 A7 ( XXXXXXX ) Item-Scale Correlation 52 - 57 F6.3 ( XX.XXX ) (Blank) 59 - 64 A6 ( XXXXXX ) Prop/Pct Endorsing Category 1 66 - 72 F7.3 ( XXX.XXX ) Prop/Pct Endorsing Category 2 104 - 110 F7.3 ( XXX.XXX ) Prop/Pct Endorsing Category 3 142 - 148 F7.3 ( XXX.XXX ) Prop/Pct Endorsing Category 4 180 - 186 F7.3 ( XXX.XXX ) Prop/Pct Endorsing Category 5 218 - 224 F7.3 ( XXX.XXX ) Prop/Pct Endorsing Category 6 256 - 262 F7.3 ( XXX.XXX ) Prop/Pct Endorsing Category 7 294 - 300 F7.3 ( XXX.XXX ) Prop/Pct Endorsing Category 8 332 - 338 F7.3 ( XXX.XXX ) Prop/Pct Endorsing Category 9 370 - 376 F7.3 ( XXX.XXX ) Prop/Pct Endorsing Category (Other) 408 - 414 F7.3 ( XXX.XXX )

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