Careless responding measures are important for several purposes, whether it's screening for careless responding or for research centered on careless responding as a substantive variable. One such approach for assessing carelessness in surveys is the use of an instructional manipulation check. Despite its apparent popularity, little is known about the construct validity of instructional manipulation checks as measures of careless responding. Initial results are inconclusive, and no study has thoroughly evaluated the validity of the instructional manipulation check as a measure of careless responding. Across 2 samples (N = 762), we evaluated the construct validity of the instructional manipulation check under a nomological network. We found that the instructional manipulation check converged poorly with other measures of careless responding, weakly predicted participant inability to recognize study content, and did not display incremental validity over existing measures of careless responding. Additional analyses revealed that instructional manipulation checks performed poorly compared to single scores of other alternative careless responding measures and that screening data with alternative measures of careless responding produced greater or similar gains in data quality to instructional manipulation checks. Based on the results of our studies, we do not recommend using instructional manipulation checks to assess or screen for careless responding to surveys.