9. Calculating Survey Weights
Once the data are collected and prepared for analysis, one must consider whether it is necessary to compute survey weights.
Survey weights are numbers associated with the respondents that specify the weight or influence the various observations should have in analysis. Weights are used to adjust for unequal probabilities of selection in the survey sampling design, unequal response rates between subsets of the intended sample, differences between the population covered by the survey frame or list and the target population, and differences between sample estimates and desired numerical controls. The final survey weight can usually be thought of as a measure of the number of population units represented by the response.