Same traits, different variance : Item-Level Variation Within Personality Measures

© 2014 the Author(s). This article has been published under the terms of the Creative Commons Attribution License. Without requesting permission from the Author or SAGE, you may further copy, distribute, transmit, and adapt the article, with the condition that the Author and SAGE Open are in each case credited as the source of the article. The version of record, Jamie S. Churcyard, Karen J. Pine, Shivani Sharma, Ben (C) Fletcher, ' Same Traits, Difference Variance: Item-Level Variation Within Personality Measures', SAGE Open, 2014, is available online via doi: 10.1177/2158244014522634Personality trait questionnaires are regularly used in individual differences research to examine personality scores between participants, although trait researchers tend to place little value on intra-individual variation in item ratings within a measured trait. The few studies that examine variability indices have not considered how they are related to a selection of psychological outcomes, so we recruited 160 participants (age M = 24.16, SD = 9.54) who completed the IPIP-HEXACO personality questionnaire and several outcome measures. Heterogenous within-subject differences in item ratings were found for every trait/facet measured, with measurement error that remained stable across the questionnaire. Within-subject standard deviations, calculated as measures of individual variation in specific item ratings within a trait/facet, were related to outcomes including life satisfaction and depression. This suggests these indices represent valid constructs of variability, and that researchers administering behavior statement trait questionnaires with outcome measures should also apply item-level variability indices.Peer reviewedFinal Published versio