To classify an item score pattern as not fitting a nonparametric item response theory (NIRT) model, the probability of exceedance (PE) of an observed response vector x can be determined as the sum of the probabilities of all response vectors that are, at most, as likely as x, conditional on the test's total score. Vector x is to be considered…

The problem of factor score indeterminacy implies that the factor and the error scores cannot be completely disentangled in the factor model. It is therefore proposed to compute Harman's factor score predictor that contains an additive combination of factor and error variance. This additive combination is discussed in the framework of classical…

Research findings indicate that response times in personality scales are related to the trait level according to the so-called speed-distance hypothesis. Against this background, Ferrando and Lorenzo-Seva proposed a latent trait model for the responses and response times in a test. The model consists of two components, a standard item response…

Models for measuring individual response precision have been proposed for binary and graded responses. However, more continuous formats are quite common in personality measurement and are usually analyzed with the linear factor analysis model. This study extends the general Gaussian person-fluctuation model to the continuous-response case and…

This article proposes several statistics for assessing individual fit based on two unidimensional models for continuous responses: linear factor analysis and Samejima's continuous response model. Both models are approached using a common framework based on underlying response variables and are formulated at the individual level as fixed regression…

Davidian-curve item response theory (DC-IRT) is introduced, evaluated with simulations, and illustrated using data from the Schedule for Nonadaptive and Adaptive Personality Entitlement scale. DC-IRT is a method for fitting unidimensional IRT models with maximum marginal likelihood estimation, in which the latent density is estimated,…

For valid decision making, it is essential to both the person being measured and the person or organization that is having the person measured that the observed scores adequately represent the underlying trait. This study deals with person-fit analysis of polytomous item scores to detect unusual patterns of sum scores on subsets of items. This…

Spearman's factor-analytic model has been proposed as a unidimensional linear item response theory (IRT) model for continuous item responses. This article first proposes a reexpression of the model that leads to a form similar to that of standard IRT models for binary responses and discusses the item indices of difficulty discrimination and…

The use of appropriateness measurement for identifying dishonest respondents on personality tests was studied through analysis of datasets of 48,725 and 1,987 in which respondents were instructed to answer honestly or dishonestly. An item response theory approach to detecting faking classified a higher number of faking respondents than did a…

This article discusses the rationale of an item response theory (IRT) model, based on Thurstone scaling, for personality measurement and suggests procedures for (a) estimating the location and slope parameters of the person response curve (PRC), (b) assessing the precision of the estimates, and (c) assessing the model-data fit. The relations…

Computed person-fit indices derived from Item Response Theory and used them to identify misfitting examinees using responses to cognitive ability and personality tests from 180 and 198 college students. Results suggest that person misfit may be related to the motivational set of the examinees. (SLD)

Examined the performance of three item-response models applied to data collected from a conventionally developed Likert-type personality scale administered to 657 Spanish undergraduates. Models' response assumptions were reasonably tenable, and the solutions obtained for the continuous, censored, and graded-response models were similar. (SLD)

This study used kernel-smoothing procedures to estimate the item characteristic functions (ICFs) of a set of continuous personality items. The nonparametric ICFs were compared with the ICFs estimated (a) by the linear model and (b) by Samejima's continuous-response model. The study was based on a conditioned approach and used an error-in-variables…

A test-retest reliability study of the Jesness Inventory based on a group of 54 male adolescents (all probationers) and a study of recidivism among 145 probationers are reported. (CTM)

True experimental designs are thought to provide internally valid results. In this investigation of the evaluations of five interventions, a source of internal invalidity is identified when self-report measures are used. An alternative approach is presented and implications of the findings for evaluation research are discussed. (JKS)