One outlier and you’re out: Influential data and racial prejudice

Currently preparing a presentation on analyzing influential data in mixed effects models myself, my eye fell on an article in which important claims on racial prejudice were refuted. An important aspect of the criticism on existing work, is that in one article the main correlation was completely due to a single observation. Solely based on this single observation, the study’s outcomes showed the Implicit Association Test (IAT) to predict overall interaction quality between White or Black people. Removing that single observation (out of 41) from the data removed the complete effect.

With survey research showing declines in “American’s endorsement of prejudice sentiments” (p.568), the question rose whether such declines actually took place, or that they are an artifact of social desirability determining respondents’ responses to survey questions. Naturally, tests like the Implicit Association Test (IAT) gained considerable attention, for the attractive claim of such tests is to be able to show levels of prejudice that people themselves are unaware of and which do not show when asked about explicitly (e.g. in a survey).
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