The importance of specifying the time period in repeated measures of personality assessments

Because most validated personality measures were designed to capture relatively general and stable characteristics, they do not specify a particular timeframe for respondents to consider. It is thus unknown how these measures perform when administered repeatedly or how this performance compares to the same measures with instructions and items adapted to the repeated timeframe of interest. We randomly assigned undergraduate participants (N = 257; M_age = 20.4; 79% female; 77% White; 77% heterosexual) to complete measures of personality (NEO-Five Factor Inventory-3, Level of Personality Functioning Scale-Brief Form-2.0, Personality Inventory for DSM-5-Brief Form, Five Factor Borderline Inventory-Short Form) with validated general instructions and items or measures with instructions and items pertaining to the previous week once per week for 6 weeks. Compared to measures with general instructions, measures with weekly instructions demonstrated greater within-person internal consistency (weekly ωs: .42-.83; general ωs: .44-.72), lower rank-order stability (weekly average 1 week r = .72; general average 1 week r = .86), greater variability (ds: .08-.94), lower average mean scores across time (ds: -.96 to .25), and stronger associations with measures of anxiety and depression, well-being, and functioning but similar between-person internal consistencies (weekly ωs: .79-.99; general ωs: .79-.99) and measurement invariance. Researchers assessing personality weekly may thus be able to capture more variability and stronger associations with relevant constructs while still maintaining reliable individual differences and construct validity using personality measures referencing participants' past week. However, nuances such as lower average scores when referencing the past week should be kept in mind when comparing results between studies using different reference timeframes. (PsycInfo Database Record (c) 2026 APA, all rights reserved).