Does Sampling Matter? Evidence from Personality and Politics

Internet surveys have provided survey methodologists with a faster, cheaper, and easier way to collect data. Nevertheless, the majority of Internet surveys suffer from a grave methodological setback–because there is no sampling frame of Internet users, the results cannot be easily generalized to the population. This project aims to contribute to the recent literature that explores the extent to which non-probability samples can be used to shed insights on the population. Using data collected in 2015 from eight different non-probability Internet samples and one Internet probability sample of the German population aged 18-70, I ask: Are there differences in correlations derived from probability and non-probability samples? I answer this by looking at correlations between the Big Five personality traits and political behaviors. Results present a mixed picture for using non-probability samples. In terms of predicting political participation and political interest, the results generated by both types of samples were statistically indistinguishable from each other. However, the results were inconsistent among the models predicting vote choice suggesting that, at least, when it comes to predicting certain political behaviors non-probability samples are not nearly as reliable as has been suggested by some.