Within-person personality variability in the work context: A blessing or a curse for job performance?

Only recently, the question whether within-person personality variability is a blessing or a curse for job performance has reached the agendas of Industrial and Organizational (I-O) psychology researchers. Yet, this limited stream of research resulted in inconsistent findings, and only little understanding exists about the role of rater source and mean-level personality in this relationship. Broadly following socioanalytic theory, the present study examined the extent to which self- and other-rated within-person personality variability predict self- and other-rated job performance, and whether this is moderated by mean-level personality. Within-person personality variability indices and job performance evaluations were obtained from an experience sampling study including N = 166 teachers, N = 95 supervisors, and N = 69 classes (including 1,354 students). Results showed that—above and beyond the effects of mean-level personality—self-rated within-person variability was positively associated with self-rated job performance, while other-rated within-person variability was negatively associated with other-ratings of performance. Many interactions with mean-level personality were found, mainly demonstrating negative effects of variability for those with a less adaptive personality profile (cf. variability as a ‘curse’), while showing positive effects of variability for those with a more adaptive trait profile (cf. variability as a ‘blessing’). Importantly, however, additional analyses provided little evidence for associations across type of rater source. These findings contribute to the field of I-O psychology by highlighting that perceptions of within-person personality variability may impact performance evaluations beyond personality traits, although its desirability seems to depend on individuals’ personality trait level. Implications and limitations are discussed.