Potential Uses of Social Surveys n objective info. re. how many of what type of people/activities are located in various places n behavioral information/from travel to sexual n attitudes/opinions re. host of issues or products

Survey Research Design Issues (“How to” issues) n SAMPLING issue n NONRESPONSE issue n QUESTION DESIGN issue n MODE OF DATA COLLECTION issue n INTERVIEWING issue

Sampling Issue n goal??? n The sample or subset of elements selected should be representative of the population under study. n Otherwise, limited generalizability. n This will be strongly influenced by: –sampling frame –sampling design

Sampling Frame n the set of people that has a chance to be selected n typically, a list or directory of members of the population to be studied n Issue??? How closely does it correspond to the population sought?

Basic Categories of Sampling Designs n Probability sampling designs –each element of the population has a known chance of being selected n Non-probability sampling designs –we cannot know the probability of each element being selected into the sample –weakness???

Types of Probability Sampling Designs n simple random sampling n systematic sampling (a variant) –sampling fraction concept –potential dangers???

Stratified Random Sampling n subdivide the population into strata (subgroups) n select elements randomly within each stratum n variant-- disproportionate stratified random sampling –vary the sampling fraction across strata n Requires adjustments in analysis stage

Multistage (Cluster) Sampling n a variation on stratified sampling n procedure……………………….. n useful when there is no master list or the population is dispersed in space n Dangers???

Longitudinal Sampling Designs n used in studies whose goal is to study changing status of variables in the population under study over time n different sampling designs are appropriate to identify different types of change

Trend Survey Sampling Designs n time 1: a population (all 20 year olds) is defined and a sample selected n time 2: a new population of 20 year olds is sampled n Permits us to answer: “How has behavior of 20 year olds changed over time?”

Cohort Survey Sampling Designs n Members of the population as originally defined are followed through time n 15 year olds in 1980; 20 year olds in 1985; 25 year olds in 1990; 30 year olds in 1995; 35 year olds in n Permits us to answer: “How has behavior of those who were 15 in 1980 changed over a 20 year period?” n variant: PANEL SURVEY DESIGN

The NONRESPONSE issue n individuals selected to be in sample who end up providing NO information n should calculate a NONRESPONSE (or COMPLETION) rate –the fraction selected for the sample who did not or did provide any data.

Nonresponse Issues n effect on survey estimates of population values from sample values n how to reduce nonresponse rate

Effect on survey estimates of population values depends on: n percentage not responding n extent to which those not responding are BIASED (differ from the whole population)

How to reduce nonresponse rate? n for telephone surveys n for mail surveys

Assignment n Review (with a focus on the flow chart): –Sparrow and O’Brien, “Attitudes toward Impeachment …” –Baser et al, “Attitudes toward Condom Availability Programs” –Weeks and Iles, “Attitudes... Bob Dole” n Study questionnaires and try to determine how each construct in the flow chart will be measured using the questionnaire