Sample Composition Effects in Alabama Senate Election Polling

The controversy surrounding Roy Moore in the Alabama Senate election seemed primed to create a differential partisan nonresponse bias phenomenon often seen in past election polling. As negative news increases about a candidate in an election, members of the public who share that candidate’s party or support the candidate become less inclined to take polls about the election. Shifts in election polling could thus result from mirages related to these nonresponse patterns, and not actual changes in opinion.

I’ve shown a similar trend using crosstabs from public polling in the context of Donald Trump approval rating polls, finding a moderately strong relationship between the partisan composition of a sample and Trump approval. I thought it might be informative to do the same with the string of pre-election polling for the upcoming Alabama Senate election. CONT.

Alexander Agadjanian