Psychological tests typically include a response scale whose purpose it is to organize and constrain the options available to respondents and facilitate scoring. One such response scale is the Likert scale, which initially was introduced to have a specific 5-point form. In practice, such scales have varied considerably in the nature and number of response options. However, relatively little consensus exists regarding several questions that have emerged regarding the use of Likert-type items. First, is there a “psychometrically optimal” number of response options? Second, is it better to include an even or odd number of response options? Finally, do visual analog items offer any advantages over Likert-type items? We studied these questions in a sample of 1,358 undergraduates who were randomly assigned to groups to complete a common personality measure using response scales ranging from 2 to 11 options, and a visual analog condition. Results revealed attenuated psychometric precision for response scales with 2 to 5 response options; interestingly, however, the criterion validity results did not follow this pattern. Also, no psychometric advantages were revealed for any response scales beyond 6 options, including visual analogs. These results have important implications for psychological scale development.

This study was conducted to establish (a) the stability of the DSM-5 Section III personality disorder (PD) traits, (b) whether these traits predict future psychosocial functioning, and (c) whether changes in traits track with changes in psychosocial functioning across time. Ninety-three outpatients (61% Female) diagnosed with at least one PD completed patient-report measures at two time-points (M time between assessments = 1.44 years), including the Personality Inventory for the DSM-5 and several measures of psychosocial functioning. Effect sizes of rank-order and mean-level change were calculated. In addition, Time 1 traits were used to predict functioning measures at Time 2. Finally, latent change score models were estimated for DSM-5 Section III traits and functioning measures, and correlations among latent change scores were calculated to establish the relationship between change in traits and functional outcomes. Findings demonstrated that the DSM-5 Section III traits were highly stable in terms of normative (i.e., mean-level) change and rank-order stability over the course of the study. Furthermore, traits prospectively predicted psychosocial functioning. However, at the individual level traits and functioning were not entirely static over the study, and change in individuals’ functioning tracked with changes in trait levels. These findings demonstrate that the DSM-5 Section III traits are highly stable consistent with the definition of PD, prospectively predictive of psychosocial functioning, and dynamically associated with functioning over time. This study provides important evidence in support of the DSM-5 Section III PD model.

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Little attention typically is paid to the way self-report measures are translated for use in self-informant agreement studies. We studied two possible methods for creating informant measures: (a) the traditional method in which self-report items were translated from the first- to the third-person and (b) an alternative meta-perceptual method in which informants were directed to rate their perception of the targets’ self-perception. We hypothesized that the latter method would yield stronger self-informant agreement for evaluative personality dimensions measured by indirect item markers. We studied these methods in a sample of 303 undergraduate friendship dyads. Results revealed mean-level differences between methods, similar self-informant agreement across methods, stronger agreement for Big Five dimensions than for evaluative dimensions, and incremental validity for meta-perceptual informant rating methods. Limited power reduced the interpretability of several sparse acquaintanceship effects. We conclude that traditional informant methods are appropriate for most personality traits, but meta-perceptual methods may be more appropriate when personality questionnaire items reflect indirect indicators of the trait being measured, which is particularly likely for evaluative traits.