1. Non-Experimental designs: Surveys & Correlational
Psych 231: Research Methods in Psychology

2. Exam 2 results Mean = 75.2 Median = 78 Max = 98 Min = 47
Most common errors
Between vs. within designs
Independent vs. dependent vars
Scales of measurement
Confounds vs. extraneous variables
Main effects vs. interactions
Exam 2 results

3. Non-Experimental designs
Sometimes you just can’t perform a fully controlled experiment
Because of the issue of interest
Limited resources (not enough subjects, observations are too costly, etc).
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

4. Stages of survey research
Stage 1) Identify the focus of the study and select your research method
Stage 2) Determining the research schedule and budget
Stage 3) Establishing an information base
Stage 4) Identify the sampling frame
Stage 5) Determining the sample method and sampling size
Review Probability and Non-Probability methods
Voluntary response method
Importance of sample size
Stages of survey research

5. Stages of survey research cont.
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)?
Stages of survey research cont.

6. Good and poor questions
Was the FDC negligent by ignoring the
warnings about Vioxx during testing
and approving it for sale?
Yes No
Unsure
Do you favor eliminating the wasteful
excess in the public school budget?
If the FDC knew that Vioxx caused serious side effects during testing,
what should it have done?
Ban it from ever being sold
Require more testing before approving it
Unsure
Do you favor reducing the public school budget?
Yes No
Problem: emotionally
charged words
Good and poor questions

7. Good and poor questions
Should senior citizens be given more
money for recreation centers and
food assistance programs?
Yes No
Unsure
Should senior citizens be given more money for recreation centers?
Yes No
Unsure
Should senior citizens be given more money for food assistance programs?
Problem: asks two
different questions
Good and poor questions

8. Good and poor questions
Are you against same sex marriage
and in favor of a constitutional
amendment to ban it?
Yes No
Unsure
What is your view on same sex marriage?
I think marriage is a matter of personal choice
I’m against it but don’t want a constitutional amendment
I want a constitutional amendment banning it
Problem: Biased in
more than one direction
Problem: Asks two
questions
Good and poor questions

9. 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?
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
Survey Questions

10. Survey Questions: Close-ended
Decide what kind of rating scales
Rating:
e.g., Likert scale
PSY 231 is an important course in the major.
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.
Survey Questions: Close-ended

11. Survey Questions: Close-ended
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

12. Stages of survey research cont.
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
Stages of survey research cont.

13. Non-Experimental designs
Sometimes you just can’t perform a fully controlled experiment
Because of the issue of interest
Limited resources (not enough subjects, observations are too costly, etc).
Surveys
Correlational
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

14. Correlational designs
Looking for a co-occurrence relationship between two (or more) variables
We call this relationship a correlation.
3 properties: form, direction, strength
Correlational designs

15. Linear
Non-linear
Form

16. Direction Positive Negative Y X Y X X & Y vary in the same direction
X & Y vary in opposite directions Y X
Direction

17. r = 0.0
“no relationship”
r = 1.0
“perfect positive corr.”
r = -1.0
“perfect negative corr.”
-1.0
0.0
+1.0
The farther from zero, the stronger the relationship
Strength

18. Correlational designs
Looking for a co-occurrence relationship between two (or more) variables
Used for
Descriptive research
do behaviors co-occur?
Predictive research
is one behavior predictive of another?
Reliability and Validity
Does your measure correlate with others (and itself)?
Evaluating theories
Look for co-occurrence posited by the theory.
Correlational designs

19. Correlational designs
Looking for a co-occurrence relationship between two (or more) variables
Example 1: Suppose that you notice that the more you study for an exam, the better your score typically is
At a descriptive level this suggests that there is a relationship between study time and test performance.
For our example, which variable is explanatory and which is response? And why?
It depends on your theory of the causal relationship between the variables
Explanatory variables (Predictor variables)
Response variables (Outcome variables)
Correlational designs

20. Y X 1 2 3 4 5 6
Hours study X
Exam perf. Y 6 1 2 5 3 4
For this example, we have a linear relationship, it is positive, and fairly strong
Scatterplot

21. Scatterplot Y 6 5 4 3 2 1 X Response (outcome) variable
For descriptive case, it doesn’t matter which variable goes where
Correlational analysis
For predictive cases, put the response variable on the Y axis
Regression analysis
Explanatory (predictor) variable
Scatterplot

22. Correlational designs
Advantages:
Doesn’t require manipulation of variable
Sometimes the variables of interest can’t be manipulated
Allows for simple observations of variables in naturalistic settings (increasing external validity)
Can look at a lot of variables at once
Example 2: The Freshman 15 (CBS story)
Is it true that the average freshman gains 15 pounds?
Recent research says ‘no’ – closer to 2.5 – 3 lbs
Looked at lots of variables, sex, smoking, drinking, etc.
Also compared to similar aged, non college students
Correlational designs

23. Correlational designs
Disadvantages:
Don’t make casual claims
Third variable problem
Temporal precedence
Coincidence (random co-occurence)
Correlational results are often misinterpreted
Correlational designs

24. Misunderstood Correlational designs
Example 3: Suppose that you notice that kids who sit in the front of class typically get higher grades.
This suggests that there is a relationship between where you sit in class and grades.
Daily Gazzett
Children who sit in the back of the classroom receive lower grades than those who sit in the front.
Possibly implied: “[All] Children who sit in the back of the classroom [always] receive worse grades than [each and every child] who sits in the front.”
Better: “Researchers X and Y found that children who sat in the back of the classroom were more likely to receive lower grades than those who sat in the front.”
Misunderstood Correlational designs
Example from Owen Emlen (2006)

25. Non-Experimental designs
Sometimes you just can’t perform a fully controlled experiment
Because of the issue of interest
Limited resources (not enough subjects, observations are too costly, etc).
Surveys
Correlational
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

26. Quasi-experiments What are they? General types
Almost “true” experiments, but with an inherent confounding variable
General types
An event occurs that the experimenter doesn’t manipulate
Something not under the experimenter’s control
(e.g., flashbulb memories for traumatic events)
Interested in subject variables
high vs. low IQ, males vs. females
Time is used as a variable
Quasi-experiments

27. Quasi-experiments Advantages Disadvantages
Allows applied research when experiments not possible
Threats to internal validity can be assessed (sometimes)
Disadvantages
Threats to internal validity may exist
Designs are more complex than traditional experiments
Statistical analysis can be difficult
Most statistical analyses assume randomness
Quasi-experiments

28. Quasi-experiments Program evaluation
Research on programs that is implemented to achieve some positive effect on a group of individuals.
e.g., does abstinence from sex program work in schools
Steps in program evaluation
Needs assessment - is there a problem?
Program theory assessment - does program address the needs?
Process evaluation - does it reach the target population? Is it being run correctly?
Outcome evaluation - are the intended outcomes being realized?
Efficiency assessment- was it “worth” it? The the benefits worth the costs?
Quasi-experiments

29. Quasi-experiments Nonequivalent control group designs
with pretest and posttest (most common)
(think back to the second control lecture)
participants
Experimental
group
Control
Measure
Non-Random
Assignment
Independent Variable
Dependent Variable
But remember that the results may be compromised because of the nonequivalent control group (review threats to internal validity)
Quasi-experiments

30. Quasi-experiments Interrupted & Non-interrupted time series designs
Observe a single group multiple times prior to and after a treatment
Obs Obs Obs Obs Treatment Obs Obs Obs Obs
Look for an instantaneous, permanent change
Interrupted – when treatment was not introduced by researcher, for example some historical event
Variations of basic time series design
Addition of a nonequivalent no-treatment control group time series
O O O T O O O & O O O _ O O O
Interrupted time series with removed treatment
If treatment effect is reversible
Quasi-experiments