6 - Contemporary Polling and Nonignorable Nonresponse

Summary

This chapter explores the challenges of polling in light caused by nonignorable nonresponse. Nonprobability polling approach comes off poorly for reasons that harken back to the Literary Digest fiasco. The random sampling is far from perfect, but here we rename it the random contact approach – because what is random is who they contact, not who responds once contacted – and show that using random contact shifts error from being proportional to the population size – which can be catastrophic – to being proportional to response rates – which is not great, but much better. Section 6.1 assesses the big data approach by introducing the idea of effective sample size, a concept that allows us to compare potentially large nonrandom samples to their random sampling equivalents. Section 6.2 assesses the random contact approach that has become the last refuge of those clinging to the random sampling paradigm. Section 6.3 decomposes sampling error into elements associated with the choosing whom to contact and elements associated with individual choices given that they are contacted. This section helps clarify where the biggest threats are throughout the survey process.