Predicting consistent psychological test item responses: A comparison of models

Abstract The efficacy of four models for predicting the stability of a given individual's test item responses on a structured inventory was examined. Two models were based on item characteristics alone and predicted that an individual would be most likely to change responses to items with moderate endorsement probabilities, or with moderate social desirability scale values. Two other prediction models incorporated individual differences in the perception of item characteristics by predicting that unstable items would have relatively long response latencies for an individual, or would be near an individual's threshold for responding desirably to items. Results from two studies yielded support for the following conclusions: (a) a person's test item responses are relatively stable over short time intervals; (b) items to which a person will show response changes on retest can be identified to a statistically significant degree; (c) the models based on response latencies constituted in both studies a significantly better predictor than the other models examined. The implications of these results for the threshold model were discussed as were the practical and theoretical applications of the response latency-item stability relationship at the level of an individual's test protocol.