EBI Statistics 101

There are three basic types of questions used within an EBI survey:

• Categorical• Scaled• Text

Survey Questions

• Allows the data to be divided into groups• Example: gender or race

• Often referred to as a “demographic question”

• A categorical question allows respondents to place themselves into exactly one category

• A demographic categorical question characterizes the respondent’s personal attributes

• A demographic question is a type of categorical question

Categorical Question

• Allow respondents to indicate how strongly they feel about a question or statement using a rating scale

• Good for gauging the respondent’s attitude

• Example:

Scaled Questions

• Is considered “open-ended”• Allows respondents to write an answer in their

own words

Example:

Text Question

• Mean response• Standard deviation• Frequency distribution• Factor means

Basic Statistical Terms

• Is an average• Is only used on scaled questions• Is computed by taking the sum of all the

numerical responses to a question and dividing that sum by the number of people who answered the question

• N/A (not applicable) responses are omitted from the mean

Mean Response

Tells how tightly the responses are clustered around the mean; a measure of dispersal, or variation, in the responses

Standard Deviation

Mean = 4.00Small Standard Deviation

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Question Response

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Mean = 4.06Large Standard Deviation

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Question Response

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Responses are

clustered near the

mean

Responses are

dispersed from the

mean

If the responses are close to the mean, we expect to see a low standard deviation.

This shows the respondents answered the question in a similar manner.

In contrast, if the responses are spread across a greater range, the standard deviation will be higher.

Standard Deviation

Higher standard deviation is often interpreted as higher volatility, because more respondents answered one extreme or the other.

In comparison, lower standard deviation would likely be an indicator of stability.

The most consistent responses are those with the lowest standard deviation.

Standard Deviation

Shows the number or percent of individuals that selected each of the responses for the corresponding question

Frequency Distribution

Key Text N(1) not at all 133 (3.3%)(2) 143 (3.5%)(3) 212 (5.2%)(4) moderately 725 (17.7%)(5) 831 (20.3%)(6) 1074 (26.3%)(7) extremely 972 (23.8%)

Key Text shows the answers

to the question

N showsthe number ofpeople whoresponded

Frequency distributions can also be formed by grouping responses together.

Frequency Distribution

Key Text Nanswered 1 or 2 276 (6.8%)answered 3, 4, or 5 1768 (43.2%)answered 6 or 7 2046 (50.1%)

If each category represents an equal portion of the participants, it indicates there is little agreement among the participants.

If one category represents a large portion of the participants, then there is a large degree of agreement among the participants. This reflects a common level of satisfaction.

Frequency Distribution

• A group of questions statistically tied together

• A factor describes a broad concept more accurately than a single question does

Dining Services Factor

Factors

How satisfied are you with the following aspects of the dining services?

•Food quality•Cleanliness•Atmosphere•Hours

• Overall program effectiveness or overall satisfaction is typically the dependent factor

• The remaining factors are typically the independent factors

Dependent and Independent Factors

• A statistical method used to predict the value of the dependent variable (typically the “Overall Program Effectiveness” factor) by studying its relationship with the independent variables (typically all other factors)

• Tells us the level of impact the independent factors have on the overall factor

Regression

Suppose you examined the mean response to a question asked of male and female participants.

In all likelihood, the mean for males will be different than the mean for females.

Statistical testing reveals whether the difference occurred as the result of random chance, or if there is a real difference between the way men and women perceive the question.

Statistical Testing

Categorical – tests for a real difference in the mean of two categories Example: men vs. women

Longitudinal – tests for a real difference in the mean from one year to the next

Example: 2009 vs. 2010

External – tests for a real difference in the means of your institution and comparison institutions

Example: your institution vs. select 6

Statistical Testing

An improvement process in which an institution compares its performance against other institutions and uses the information to improve its own performance

Two types of benchmarking- internal external

Benchmarking

Longitudinal – shows where you have made improvements and where improvements could be made

Unit/Category – shows which units or categories performed at a higher level

Internal Benchmarking

Select 6 – compares your institution to six participating peer institutions of your choice

Carnegie Class – compares your institution to a group of similar institutions

All Institutions – compares your institution to all other participating institutions combined

External Benchmarking

If you have questions or need more information, please contact:

EBI Help Desk417-429-0081

helpdesk@webebi.com

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