ABSTRACT
Traditionally, personality researchers have adopted a nomothetic perspective and understood personality as relatively stable interindividual differences in how people generally feel, think, and behave. To delve beyond traditional self-report trait measurements and to acknowledge the more idiographic perspective on personality, researchers have increasingly targeted states. Despite the success of the trait perspective on personality, however, it has been severely challenged within the person–situation debate. Facilitated by advances in theory, assessment, and data analysis, researchers have become increasingly interested in the study of within-person variability – that is, in how individuals fluctuate in momentary feelings, thoughts, behaviour, and performance across time and situations. Respective mean- and/or trend-corrected quantifications should capture both overall instability and temporal dependency of repeated states, and analyses should rather follow a one-step than a two-step approach. With the aim of quantifying a person’s within-person variability based on repeated assessments of states, researchers can select from a plethora of suggested statistical indices.
