Caring about carelessness: Participant inattention and its effects on research

•We examined the effects of inattentive responding on data quality.•Multiple indicators formed latent classes of inattention replicating prior work.•Across multiple samples, 3–9% of respondents were highly inattentive.•Inattentive responding obscured regression and experimental results.•Screening out inattentive respondents improved statistical power.

The current studies examined the adverse effects of inattentive responding on compliance with study tasks, data quality, correlational analyses, experimental manipulations, and statistical power. Results suggested that 3–9% of respondents engaged in highly inattentive responding, forming latent classes consistent with prior work that converged across existing indices (e.g., long-string index, multivariate outliers, even–odd consistency, psychometric synonyms and antonyms) and new measures of inattention (the Attentive Responding Scale and the Directed Questions Scale). Inattentive respondents provided self-report data of markedly poorer quality, sufficient to obscure meaningful regression results as well as the effects of experimental manipulations. Screening out inattentive respondents improved statistical power, helping to mitigate the notable drops in power and estimated effect sizes caused by inattention.