Psych 231: Research Methods in Psychology. Announcements I will aim to have the exams graded and...
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Transcript of Psych 231: Research Methods in Psychology. Announcements I will aim to have the exams graded and...
Psych 231: Research Methods in Psychology
Announcements
I will aim to have the exams graded and entered into ReggieNet by Monday
Remember that piloting is happening in labs this week
Non-Experimental designs
Sometimes you just can’t (or don’t want to) perform a fully controlled experiment Because of the issue of interest Limited resources (not enough subjects, observations are too
costly, etc.).
There are other kinds of designs that may be used• Surveys
• Correlational studies
• Quasi-Experiments• Developmental designs
• Small-N designs
This does NOT imply that they are bad designs Just remember the advantages and disadvantages of each
Non-Experimental designs
Sometimes you just can’t (or don’t want to) perform a fully controlled experiment Because of the issue of interest Limited resources (not enough subjects, observations are too
costly, etc.).
There are other kinds of designs that may be used• Surveys
• Correlational studies
• Quasi-Experiments• Developmental designs
• Small-N designs
This does NOT imply that they are bad designs Just remember the advantages and disadvantages of each
Surveys
What are they? Questionnaires and interviews that ask people to
provide information about themselves Why conduct them?
Best way to collect some kinds of information:• Descriptive, behavioral, and preferential
• e.g., demographic information, recreational behavior, personal preferences, and attitudes
To compliment experimental work• Good/common first step, can collect a lot of data about a
lot of variables• Do not have to directly observe behaviors
http://www.people-press.org/
A good resource:
Check out the Methodology Pages
Surveys
Advantages One can investigate internal events
• e.g., attitudes & opinions
Can generalize about an entire population based on relatively small samples of individuals
Large amounts of data can be collected quickly with relatively little cost (effort, time, etc.)
• But they’re often not as “cheap” as you may think
Surveys
Disadvantages Correlational: causal claims shouldn’t be made
• Often used for descriptive and predictive research questions
• Note: surveys are sometimes used as part of an experimental design, which may allow testing of causal claims
Non-response bias• Why doesn’t everybody respond?• Does response rate interact with variables of interest?
Self-reports may not be truthful• Response set - tendency to respond from a particular
perspective• Social desirability bias (e.g., how a “moral” person would answer)
Large data sets are sometimes difficult to analyze
11 Stages of survey research
Stage 1) Identify the focus of the study and select your research method What are the objectives of the research? Is a survey method the best approach? What kind of survey should be used?
• Group administration• Mail surveys• Internet surveys• Telephone surveys• Face-to-face interviews• Focus group interviews
11 Stages of survey research
Stage 2) Determining the research schedule and budget
Stage 3) Establishing an information base Find out what’s been done, what’s known
• E.g., Find other related surveys
Stage 4) Identify the sampling frame The actual population that the sample is drawn
from (as opposed to the ideal population)• Think of it as operationalizing the conceptual level
population• Be aware of potential coverage error – when the
sampling doesn’t lead to a good representativeness
11 Stages of survey research
Stage 5) Determining the sample method and sampling size Review Probability and Non-Probability methods
• Voluntary response method
Importance of sample size
Voluntary response methods
A kind of convenience sampling methods commonly used
• Problem: Typically only individuals with strong opinions respond, so the results are often extremely biased (A coverage error issue? Non-response issue?)
Should leftover Halloween candy be given out to students who get an A on the exam?
Should leftover Halloween candy be given out to students who get an A on the exam?
Call 123-NONO if you think NOCall 123-4YES if you think YES
Daily show clip(5:30 mins)
Importance of sample size
Confidence intervals• An estimate of the mean or percentage of the population,
based on the sample data • “John Doe has 55% of the vote, with a margin of error ± 3%”
• Margin of error (that “± 3%” part)• The larger your sample size, the smaller your margin
of error will be. • Which would you be more likely to believe
• “We asked 10 people …”• “We asked 1000 people …”
Sampling error - how is the sample different from the population?
Often focus on this partBut this part is important too
Importance of sample size
Sampling error - how is the sample different from the population?
Response rate • What proportion of the sample actually responded to
the survey?• Hidden costs here - what can you do to increase
response rates
• Non-response error (bias)• Is there something special about the data that you’re
missing (From the people who didn’t respond)?
11 Stages of survey research
Stage 6) Designing the survey instrument Question construction: How the questions are
written is very important• Clearly identify the research objectives
• Do your questions really target those research objectives (think Internal and External Validity)?
• Take care wording of the questions• Keep it simple, don’t ask two things at once, avoid
loaded or biased questions, etc.• How should questions be answered (question type)?
Good and poor questions
GoodPoorWas the FDC negligent by ignoring the warnings about Vioxx during testingand approving it for sale?
a) Yesb) Noc) Unsure
Do you favor eliminating the wasteful excess in the public school budget?
a) Yesb) Noc) Unsure
If the FDC knew that Vioxx caused serious side effects during testing,what should it have done?
a)Ban it from ever being soldb)Require more testing before approving itc)Unsure
Do you favor reducing the public school budget?
a)Yesb)Noc)Unsure
Problem: emotionally charged words
Problem: emotionally charged words
Good and poor questions
GoodPoorShould senior citizens be given moremoney for recreation centers and food assistance programs?
a)Yesb)Noc)Unsure
Should senior citizens be given more money for recreation centers?
a)Yesb)Noc)Unsure
Should senior citizens be given more money for food assistance programs?
a)Yesb)Noc)Unsure
Problem: asks two different questions
Problem: asks two different questions
Good and poor questions
GoodPoorAre you against same sex marriage and in favor of a constitutional amendment to ban it?
a) Yesb) Noc) Unsure
What is your view on same sex marriage?
a) I think marriage is a matter of personal choice
b) I’m against it but don’t want a constitutional amendment
c) I want a constitutional amendment banning it
Problem: Biased inmore than one direction
Problem: Biased inmore than one direction
Problem: Asks two questions
Problem: Asks two questions
Survey Questions
Question types Open-ended (fill in the blank, short answer)
• Can get a lot of information, but• Coding is time intensive and potentially
ambiguous
Close-ended (pick best answer, pick all that apply)• Easier to code• Same response alternatives for everyone• Take care with your labels
• Decide what kind of scale
• Decide number/label of response alternatives
What is the best thing about ISU? (choose one)
1. Location 2. Academics 3. Dorm food 4. People who sell
things between Milner and the Bone
What is the best thing about ISU?
Decide what kind of rating scales• Rating: e.g., Likert scale
Survey Questions: Close-ended
PSY 231 is an important course in the major. 1 2 3 4 5 Strongly Agree Neutral Disagree Strongly Agree Disagree
• Semantic differential: Rate how you feel about PSY 231 on these dimensions
Important _____: _____: _____: _____: _____: Unimportant
Boring _____: _____: _____: _____: _____: Interesting
• Nonverbal scale for children:
Point to the face that shows how you feel about the toy.
Decide number/label of response alternatives• Use odd number (mid point and equal # of responses above
and below the mid point)• Questions should be uni-dimensional (each concerned with
only one thing)• Labels should be clear
Survey Questions: Close-ended
11 Stages of survey research
Stage 7) Pre-testing the survey instrument Fix what doesn’t seem to be working
Stage 8) Selecting and training interviewers For telephone and in-person surveys Need to avoid interviewer bias
Stage 9) Implementing the survey Stage 10) Coding and entering the data Stage 11) Analyzing the data and preparing a
final report