https://doi.org/10.1177/1073191120958059 Assessment 1–17 © The Author(s) 2020 Article reuse guidelines: sagepub.com/journals-permissions DOI: 10.1177/1073191120958059 journals.sagepub.com/home/asm Article Researchers face a key problem when they must measure trait or state constructs quickly or efficiently—the measures must be brief while maintaining score reliability and valid- ity. Several situations arise that demand efficient self-report measures ranging from daily-diary and experience-sampling studies—where participants complete the same measures repeatedly—to prescreening, mass-testing, and longitudinal studies—where participants complete a large suite of mea- sures, and a premium is placed on the number of items. With the advent of mobile technology and experience- sampling techniques, the past 20 years have witnessed a groundswell of support for brief, efficient versions of extant measures, including the Single-Item Self-Esteem Scale (SISES; Robins et al., 2001), the Ten-Item Personality Inventory (TIPI; Gosling et al., 2003), the Dark Triad Dirty Dozen (Jonason & Webster, 2010; Webster & Jonason, 2013), the Eight-Item Impusivity and Sensation Seeking Scale (Webster & Crysel, 2012), the Single-Item Need to Belong Scale (Nichols & Webster, 2013), and three-item scales for (a) social anxiety (Nichols & Webster, 2015) and (b) one’s partner’s alcohol consumption (Rodriguez & Webster, 2020). These and other measures are used in a wide range of settings and have allowed for great ease of data collection in situations where time or item space is valuable (e.g., field studies, daily-diary studies, round-robin designs). One measure particularly suited for daily-dairy and experience-sampling studies is the State Self-Esteem Scale (SSES; Heatherton & Polivy, 1991). Although it can be used as a global measure of state self-esteem, the SSES can also be scored as three related-but-distinct, factor-based subscales: social, appearance, and performance (see Table 1 for items and their subscales). The SSES has been widely adopted among researchers, garnering over 2,400 citations. Nevertheless, with 20 items, it can be unwieldy and cum- bersome in situations that demand fewer items or repeated measurements. Thus, the key purposes of the present research were to (a) identify the psychometrically “best” items of the SSES’ 20 items (i.e., items with differential dif- ficulties and high discrimination); (b) test the three-factor structure; (c) test score reliability and validity; and (d) examine how the new measure performs in a laboratory aggression experiment. To these ends, we performed item response theory (IRT) analyses to identify the “best” SSES items (Study 1) and used confirmatory factor analyses 958059ASM XX X 10.1177/1073191120958059AssessmentWebster et al. research-article 2020 1 University of Florida, Gainesville, FL, USA 2 University of California, Merced, CA, USA Corresponding Author: Gregory D. Webster, Department of Psychology, University of Florida, P.O. Box 112250, Gainesville, FL 32611-2250, USA. Email: gdwebs@ufl.edu Self-Esteem in 60 Seconds: The Six-Item State Self-Esteem Scale (SSES-6) Gregory D. Webster 1 , Jennifer L. Howell 2 , and James A. Shepperd 1 Abstract With 20 items, the State Self-Esteem Scale (SSES) can be cumbersome in settings that demand efficiency. The present research created an efficient six-item version of the SSES that preserves score reliability and validity and its three- dimensional structure: social, appearance, and performance self-esteem. Item response theory and confirmatory factor analyses identified the “best” six items—two from each dimension (Study 1). Participants completed the SSES four times at 2-week intervals (Studies 2 and 3). The six-item SSES’ scores showed adequate test–retest reliability, explained substantial variance in trait-relevant measures, and showed convergent validity with related self-esteem measures. Participants completed the SSES and a laboratory experiment where they received negative feedback on an essay they had written and could retaliate against their evaluator by allocating hot sauce for them to consume (Study 4). The six-item SSES interacted with self-esteem instability in expected ways to predict hot sauce allocated. Keywords self-esteem, state self-esteem, item response theory, aggression, multilevel modeling