As researchers in the social sciences, we are often interested in studying not
directly observable constructs through assessments and questionnaires. But even
in a well-designed and well-implemented study, rapid-guessing behavior may
occur. Under rapid-guessing behavior, a task is skimmed shortly but not read and
engaged with in-depth. Hence, a response given under rapid-guessing behavior
does bias constructs and relations of interest. Bias also appears reasonable for
latent speed estimates obtained under rapid-guessing behavior, as well as the
identified relation between speed and ability. This bias seems especially
problematic considering that the relation between speed and ability has been
shown to be able to improve precision in ability estimation. For this reason, we
investigate if and how responses and response times obtained under
rapid-guessing behavior affect the identified speed–ability relation and the
precision of ability estimates in a joint model of speed and ability. Therefore,
the study presents an empirical application that highlights a specific
methodological problem resulting from rapid-guessing behavior. Here, we could
show that different (non-)treatments of rapid guessing can lead to different
conclusions about the underlying speed–ability relation. Furthermore, different
rapid-guessing treatments led to wildly different conclusions about gains in
precision through joint modeling. The results show the importance of taking
rapid guessing into account when the psychometric use of response times is of
interest.