NonExperimental designs Surveys QuasiExperiments Psych 231 Research Methods

Non-Experimental designs: Surveys & Quasi-Experiments Psych 231: Research Methods in Psychology

Announcements n n Lab attendance is critical this week because group projects are being administered n Attendance will be taken. Turn in the group project rating sheet 1

Non-Experimental designs n Sometimes you just can’t perform a fully controlled experiment n n Because of the issue of interest Limited resources (not enough subjects, observations are too costly, etc). • • n Surveys Quasi-Experiments Developmental designs Small-N designs This does NOT imply that they are bad designs n Just remember the advantages and disadvantages of each

Surveys n What are they? (review chapter 7) n n Questionnaires and interviews that ask people to provide information about themselves Why conduct them? n 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 n Best way to collect some kinds of information: • Descriptive, behavioral, and preferential • (e. g. demographic information, recreational behavior, and attitudes)

Surveys n Advantages n n n One can investigate internal events (for example, 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 n Disadvantages n n Correlational: causal claims shouldn’t be made Non-response bias • Why doesn’t everybody respond? • Does response rate interact with variables of interest? n n Large data sets are sometimes difficult to analyze Self-reports may not be truthful • Response set - tendency to respond from a particular perspective (e. g. , how a “moral” person would answer)

Stages of survey research n Stage 1) Identify the focus of the study and select your research method n n n What are the objectives of the research? Is a survey method the best approach? What kind of survey should be used?

Surveys methods n Many different methods are used to administer surveys n n n Group administration (e. g. MASS testing session) Mail surveys Internet surveys Telephone surveys Face-to-face interviews Focus group interviews

Stages of survey research cont. n n Stage 2) Determining the research schedule and budget Stage 3) Establishing an information base n Find out what’s been done, what’s known • E. g. , Find other related surveys n Stage 4) Identify the sampling frame n The actual population that the sample is drawn from (as opposed to the ideal population) • Think of it as operationalizing the conceptual level population

Stages of survey research cont. n Stage 5) Determining the sample size and sampling method n Review Probability and Non-Probability methods (Oct. 10 lecture)

Voluntary response methods n A kind of convenience sampling methods commonly used Should leftover Halloween candy be given out to students who get an A on the exam? Call 123 -4 YES if you think YES Call 123 -NONO if you think NO • Problem: You typically get only individuals with strong opinions to respond, so the results are often extremely biased

Importance of sample size n Sampling error - how is the sample different from the population? n Confidence intervals • An estimate of where the mean or percentage in the overall population is, based on the sample data • “John Doe has 55% of the vote, with a margin of error ± 3%” • Margin of error (that “± 3%” part) • Which would you be more likely to believe • We asked 10 people … • We asked 1000 people … • The larger your sample size, the smaller your margin of error will be.

Stages of survey research cont. n Stage 6) Designing the survey instrument n Question construction: How the questions are written is very important • Clearly identify the research objectives • Do your questions really target those research objectives? • 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?

Good and poor questions Poor Was the FDC negligent by ignoring the warnings about Vioxx during testing and approving it for sale? Problem: emotionally charged words a) Yes b) No c) Unsure Good If the FDC knew that Vioxx caused serious side effects during testing, what should it have done? a) Ban it from ever being sold b) Require more testing before approving it c) Unsure

Good and poor questions Poor Are you against same sex marriage and in favor of a constitutional amendment to ban it? Problem: a) Yes Biased in more b) than No one direction c) Unsure Good 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

Survey Questions n Question types n Open-ended (fill in the blank, short answer) • Can get a lot of information, but • Coding is time intensive and potentially ambiguous n Close-ended (pick best answer, pick all that apply) • Easier to code • Response alternatives are the same for everyone n Rating scales • Used for “how much” judgments • e. g. , Likert scale – measures attitudes, agree/disagree • Take care with your labels • Range of scores, anchors

Stages of survey research cont. n Stage 7) Pre-testing the survey instrument n n Stage 8) Selecting and training interviewers n n n Fix what doesn’t seem to be working 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

Error in survey research n n Measurement error Sampling error

Error in survey research n Measurement error n Same old issues of validity and reliability • Are your questions really measuring what you want them to? • Do you get similar answers with repeated questions

Error in survey research n n Measurement error Sampling error n n Are there differences in your sample (compared to the population as a whole)? 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

Quasi-experiments What are they? n n n Almost “true” experiments, but with an inherent confounding variable General types 1) An event occurs that the experimenter doesn’t manipulate • Something not under the experimenter’s control • (e. g. , flashbulb memories for traumatic events) 2) Interested in subject variables – high vs. low IQ, males vs. females 3) Time is used as a variable

Quasi-experiments n Advantages n n Allows applied research when experiments not possible Threats to internal validity can be assessed (sometimes)

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

Quasi-experiments n Interrupted time series designs n Observe a single group multiple times prior to and after a treatment Obs Obs Treatment Obs Obs • Look for an instantaneous, permanent change n Variations of basic time series design n Addition of a nonequivalent no-treatment control group time series OOOTOOO n & OOO_OOO Interrupted time series with removed treatment • If treatment effect is reversible

Next time Go to labs this week, attendance will be taken n Non experimental designs cont. n n n Read chapters 9 & 13 Reminder, journal summary 2 is coming up