A Coordinated Analysis of Variance in Affect in Daily Life

Abstract

Despite widespread interest in variance in affect, basic questions remain pertaining to the relative proportions of between-person and within-person variance, the contribution of days and moments, and the reliability of these estimates. We addressed these questions by decomposing negative affect and positive affect variance across three levels (person, day, moment), and calculating reliability using a coordinated analysis of seven daily diary, ecological momentary assessment (EMA), and diary-EMA hybrid studies (across studies age = 18-84 years, total N_persons = 2,103, total N_observations = 45,065). Across studies, within-person variance was sizeable (negative affect: 45% to 66%, positive affect: 25% to 74%); in EMA more within-person variance was attributable to momentary rather than daily level. Reliability was adequate to high at all levels of analysis (within-person: .73-.91; between-person: .96-1.00) despite different items and designs. We discuss the implications of these results for the design of future intensive studies of affect variance.

Keywords: affect; daily diary; ecological momentary assessment; intensive longitudinal design; variability.

Figure 1.

Percentages of Between (Shaded) and Within (Unshaded) Person Variance in Negative Affect (NA) in End of Day (EOD) and Ecological Momentary Assessment (EMA) Reports. For each dataset, percent between-person variance is displayed in grey shaded portions of the bars and percent within-person variance is displayed in the unshaded portions. In momentary datasets, within-person variance can be decomposed into two sources, variation within-persons across days (the lower portion of the unshaded area) and variation within-persons within days (the upper dotted portion of the unshaded area). ESCAPE and SAWM are hybrid designs containing both EOD and momentary reports, thus the EOD data from the hybrid studies is presented with the diary studies and the momentary data from these hybrid studies is presented with the EMA studies.

Figure 2.

Percentages of Between- (Shaded) and Within- (Unshaded) Person Variance in Positive Affect (PA) in End of Day (EOD) and Ecological Momentary Assessment (EMA) Reports. For each dataset, percent between-person variance is displayed in grey shaded portions of the bars and percent within-person variance is displayed in the unshaded portions. In momentary datasets, within-person variance can be decomposed into two sources, variation within-persons across days (the lower portion of the unshaded area) and variation within-persons within days (the upper dotted portion of the unshaded area). ESCAPE and SAWM are hybrid designs containing both EOD and momentary reports, thus the EOD data from the hybrid studies is presented with the diary studies and the momentary data from these hybrid studies is presented with the EMA studies.

Figure 3.

Plots for estimated reliability of within-person (R_WP) assessments of negative affect (NA) and positive affect (PA) based on coordinated analyses of End of Day (EOD) and Momentary datasets. ESCAPE and SAWM are hybrid designs containing both EOD and momentary reports, thus the EOD data from the hybrid studies is presented with the diary studies and the momentary data from these hybrid studies is presented with the Ecological Momentary Assessment (EMA) studies.