The Measurement of Variability and Change in Life Satisfaction: A Comparison of Single-Item and Multi-Item Instruments.

In many large-scale surveys, life satisfaction is measured with a single item. Little is known about how sensitive single-item instruments react to changes across time or in the face of critical life events. The present study draws on a Dutch sample of N = 4,034 participants who were administered three different single items and an established multi-item instrument at four annual surveys within 6 years. An indicator-specific latent state-trait growth model was employed to estimate the agreement in change coefficients for the different instruments. The results indicated that single items estimated a similar developmental decline in life satisfaction across the life course as multi-item scales, but they were less sensitive to the loss of paid work. Interindividual differences in intraindividual change were better captured with multiple items. Moreover, single items reflected occasion-specific variance to a larger degree than longer scales. In addition, occasion-specific effects were larger among younger respondents as compared to older age groups. Therefore, single items appear to represent valid measures for the estimation of the average change in life satisfaction within a sample. However, they might exhibit a low power to detect moderating influences on the estimated change trajectories and capture less trait variance than multi-item scales. [ABSTRACT FROM AUTHOR]