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

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

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, 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

Surveys Advantages 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 Disadvantages Correlational: causal claims shouldn’t be made 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? Large data sets are sometimes difficult to analyze 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 )

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

Stages of survey research cont. 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

Stages of survey research cont. 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 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 clipAnother fun poll result

Importance of sample size Sampling error - how is the sample different from the population? 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 …”

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)?

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)?

Good and poor questions GoodPoor Was the FDC negligent by ignoring the warnings about Vioxx during testing and approving it for sale? a)Yes b)No c)Unsure 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 Problem: emotionally charged words Problem: emotionally charged words

Good and poor questions GoodPoor Are you against same sex marriage and in favor of a constitutional amendment to ban it? a)Yes b)No c)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 in more than one direction Problem: Biased in more 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 Response alternatives are the same for everyone Rating scales Used for “how much” judgments e.g., measures attitudes, agree/disagree Take care with your labels Range of scores, anchors

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