Chapter 9 Survey Methodology Basic survey language Types of surveys The survey schedule Survey designs Sampling error, confidence levels, and sample size

Basic Survey Language In research, the term survey refers to a sample survey A sample survey has scientific utility

Types of Surveys Four basic types of ways to collect survey data: In person On the phone Through the mail On the internet

The Survey Schedule (Questionnaire) The interviewer/survey script Length Writing the schedule

Survey Designs There are three basic survey designs: Cross sectional design survey Panel study Multiple cross sections

Cross Sectional Survey Design Analogous to a photographa snapshot in time Generalizable only to the sample population during that period of time

Panel Study A single sample is interviewed at multiple points in time Allows us to see change in a particular group Introduces threats to validity (testing and sensitivity)

Multiple Cross Sections or Continuous Polling Multiple cross sections: different samples are pulled from a particular population over time for comparison Continuous polling: interviews take place for weeks or months at a time; the researcher combines the respondents’ data for time periods

Mortality A potential threat to validity; the death of a sample element If a respondent in a panel designs stops being interviewed Multiple cross sections avoid mortality problems, but present sampling challenges

Interpreting Statistical Numbers Three basic interdependent quantities must be known: Sampling error Confidence level Sampling size

Sampling Error The error rate is how far off the sample statistic is likely to be from the population parameter that is being estimated (the population’s true score)

Confidence Level The probability / likelihood that the actual population parameter is in the range of the sampling error The wider the range, the more certain we are that the range encompasses that actual population parameter; the narrower the range, the less certain

Sample Size (N) The number of people or things in the sample