6. Survey and Sampling

1. 6. Survey and Sampling • When and why are surveys used in behavioral research? • What are the advantages and disadvantages of using interviews versus questionnaires in survey research? • How is probability sampling used to ensure that a sample is representative of the population? • What is sampling bias, and how does it undermine a researcher’s ability to draw conclusions about surveys? • What statistical procedures are used to report and display data from surveys? • What is the margin of error of a sample?

2. Survey: A series of self-report measures, administered either through an interview or a written questionnaire. It aims at producing a “snapshot” of the opinions, attitudes, or behaviors of a group of people at a given time.

3. Survey Do you meet (call) participants or mail them? Do you focus on a small group or large samples? Meet a small group Mail large samples Interview Questionnaire Do you use free format? Do you create questionnaire? Yes No Yes No Unstructured Interview Survey of Existing Data Structured Interview Survey of Your original Questionnaire

4. Interviews The research method in which researcher ask questions to respondents generally in a face-to-face setting. Interviews allow the researcher to develop a close rapport and sense of trust with the respondents X Face to face interviews are extremely expensive to conduct. Alternative: telephone interview

5. Unstructured Interview The researcher uses either free-format or semi-fixed-format self-report measure. It provides in-depth information about the particular concerns of an individual. However, the interviewers need to be well trained so that they can collect certain information through free conversation. It is also difficult to maintain objectivity. Focus Group: Shared ideas both with interviewer and respondents. Structured Interview The researcher generally uses fixed-format items and reads the questions to the respondents. It allows better comparison of the responses across different individuals.

6. Questionnaires A set of fixed-format, self-report items that is completed by respondents at their own pace, often without supervision. Use of Original Questionnaire Generally cheaper than interviews because the researcher mails the questionnaire or has them complete the questionnaire in large group. X The respondent may misunderstand the questions. The respondents may ask another person to answer the questions.

7. The Response Rate Discussion: How can we got more responses? e.g. Kitayama, Karasawa, and Masuda (1995) The Survey of the Earthquake Perception The Question Order Discussion: How can we cope with this problem? e.g. Norbert et al (1999) Happiness??

8. Use of Existing Survey Data e.g. The U.S. Census (General Social Survey) Assignment#4: Finding useful database for your research. 1. Go to http://www.icpsr.umich.edu 2. With your group members, find one of the research domains which you think interesting. 3. Open the abstract (AB) of each database and summarize them 4. Discuss what kind of research is possible with these datasets. 5. Report what you discussed in the class.

9. Sampling and Generalization Sampling: The selection of people to participate in a research project, usually with the goal of being able to use these people to make inferences about a larger group of people. X X X X X X X X X X X X XX X X X X X X X Sampling Population

10. How do you collect samples? 1. Define the Population (e.g. Average American Collage Students) 2. Consider Representative Samples in the group. X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X XX X X X X X X X = Male Student X = Female Students

11. 3. Decide Sampling Methods Probability Sampling: A sampling procedure ensuring that each person in the population has a known chance of being selected to be a part of sample. Sampling Bias Non Probability Sampling A sampling procedure used in cases where probability sampling is impossible because there is no available frame. e.g. homeless people

12. Sampling Do you know the population That you want to sample? Probability Sampling Yes Cluster Sampling No No Do you have lists? Yes Non-Probability Sampling Is the list already random? No Are there subgroups in the list? Yes No Yes Do you run experiment, setting up the time? Systematic Random Sampling Stratified Sampling Yes No Proportionate? No Yes Convenient Sampling Snowball Sampling Simple Random Sampling Disproportionate Stratified Sampling Proportionate Stratified Sampling

13. Simple Random Sampling In case each person in the population has an equal chance of being selected to be in the sample, the researcher uses random numbers to collect samples. (See Appendix E, Statistical Table 2) 3 8 12 17 18 33 40 45 46 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 When you use SPSS, 1.Go to “Data” menu 2.Click “Select Cases” 3.Choose “Random Sample of Cases” 4.Click “Sample” 5.Enter exact number that you want to sample and the total number of the data.

14. Systematic Random Sampling In case the sampling frame is itself known to be in a random sequence, then the researcher randomly chooses the first sample and then add certain stable numbers to get the next sample. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 3 + 5

15. Stratified Sampling In case there are some subgroups in the sampling frame, the researcher breaks the frame into subgroups (strata), and randomly samples in each subgroups. Proportionate Stratified Sampling X X X X X X X X X X X X X X X X X X X X X X X X X X X X X Disproportionate Stratified Sampling Oversampling X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X

16. Cluster Sampling In case there is no complete sampling frame, the researcher breaks the possible “population” into a set of smaller groups (called clusters) for which there are sampling frames and then to randomly choose Some of the clusters for inclusion in the sample. X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X

17. New England USA Mid-Atlantic CT MA ME RI VT NY NJ PA MSU UM EMU CMU WMU CT MA ME NH RI VT NJ NY PA IA IL IN KS MI MN MO NB ND OH SD WI CA OR WA AZ CO ID MT NM NV UT WY AR LA OK TX AL DE FL GA KY MD MS NC SC TN WV VA Midwest IA IL IN KS MI MN MO NB ND OH SD WI Mountain AZ CO ID MT NM NV UT WY South AL DE FL GA KY MD MS NC SC TN WV VA X X X X X X X X X X X X X X X X X X X X X X X Southwest Pacific AR LA OK TX CA OR WA

18. Snowball Sampling The researcher contacts one or more individuals from the population, and these individuals are used to lead the researcher to other population members. X X X X X X X X X X X X X X X X X X R = X

19. Convenient Sampling The researcher samples whatever individuals were readily available without any attempt to make the sample representative of a population. Commonly used in experimental design. Experiment 381 9/22/00 1:00_______________ 2:00_______________ 3:00_______________ 4:00_______________ 5:00_______________ X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X XX X X X X X X X X X X X X X X X X X X X X X X X X X X X X X