Psychometric Analysis of the Modified Differential Emotions Scale and the Six-Item Life Orientation Test-Revised in a Cohort of Older Women from the Women's Health Initiative

Abstract

Background: Positive affect and emotional resources, such as optimism, may play a major role in women's health and promote healthy well-being later in life. However, positive affect and optimism measures have not been psychometrically assessed in older women, despite relations to health. Therefore, the objective of this study was to psychometrically assess measures of positive affect and optimism and test their association with other measures of well-being. Methods: In a Women's Health Initiative subcohort of 58,810 women (mean age [standard deviation] 79.0 [6.1]; 89% White), positive affect and optimism were measured using the modified Differential Emotions Scale (mDES) and Life Orientation Test-Revised (LOT-R), respectively. Reliability was tested using Cronbach's alpha and McDonald's omega. Performance was assessed using item response theory. Factor analysis was used to explore the construct validity of the LOT-R. Convergent and divergent validity with other well-being measures was tested. Results: Results suggest good reliability (mDES: Cronbach's alpha = 0.90 and omega total = 0.92; LOT-R: Cronbach's alpha = 0.79, omega hierarchical = 0.61, and omega total = 0.83). Item response analyses indicate mDES's ability to discriminate across positive affect; LOT-R was skewed toward lower optimism levels. Exploratory factor analyses suggest a two-factor solution for the LOT-R. Significant, but small correlations in expected directions to well-being measures confirmed validity hypotheses. Conclusions: The mDES and LOT-R measured positive affect and optimism with good reliability, item performance, and validity in a large sample of older postmenopausal women, supporting use of these measures to quantify effects of positive affect and optimism-promoting interventions.

Keywords: mental health; optimism; positive affect; postmenopausal women; psychometrics.

FIG. 1.

Option characteristic curves for the mDES, estimated from nonparametric item response theory models among Women's Health Initiative Extension Study 2 participants, 2014–2015 (n = 58,810). The x-axis represents the spectrum of underlying latent trait of positive affect and the y-axis represents probability of selecting an option. mDES, modified Differential Emotions Scale.

FIG. 2.

Option characteristic curves for the six-item LOT-R, estimated from nonparametric item response theory models among Women's Health Initiative Extension Study 2 participants, 2014–2015 (n = 58,810). *Indicates reverse scored item. The x-axis represents the spectrum of underlying latent trait of optimism and the y-axis represents probability of selecting an option. LOT-R, Life Orientation Test-Revised.

FIG. 3.

Test information and standard error of measurement curves for the mDES and six-item LOT-R items (n = 58,810). The x-axis represents the level of the underlying latent trait of optimism or positive affect. The y-axis represents the amount of information provided by the test or standard error.

FIG. 4.

Differential item function plots for the mDES comparing ≤high school/GED versus at least some college (n = 58,428). The x-axis represents the spectrum of underlying latent trait of positive affect and the y-axis represents the expected score for each item. n = 382 missing education level. GED, General Education Development.

FIG. 5.

Differential item function plots for the six-item LOT-R comparing ≤high school/GED versus at least some college (n = 58,428). The x-axis represents the spectrum of underlying latent trait of optimism and the y-axis represents the expected score for each item. n = 382 missing education level. GED, General Education Development. *Indicates reverse scored item.