Refinement and revalidation of the demoralization scale: The DS-II-external validity

Abstract

Background: The recently refined Demoralization Scale-II (DS-II) is a 16-item, self-report measure of demoralization. Its 2 factors-Meaning and Purpose and Distress and Coping Ability-demonstrate sound internal validity, including item fit, unidimensionality, internal consistency, and test-retest reliability. The convergent and discriminant validity of the DS-II with various measures is reported here.

Methods: Patients who had cancer or other progressive diseases and were receiving palliative care (n = 211) completed a battery of questionnaires, including the DS-II and measures of symptom burden, quality of life, depression, and attitudes toward the end of life. Spearman ρ correlations were determined to assess convergent validity. Mann-Whitney U tests with calculated effect sizes were used to examine discriminant validity and establish the minimal clinically important difference (MCID). Cross-tabulation frequencies with chi-square analyses were used to examine discriminant validity with major depression.

Results: The DS-II demonstrated convergent validity with measures of psychological distress, quality of life, and attitudes toward the end of life. It also demonstrated discriminant validity, as the DS-II differentiated patients who had different functional performance levels and high/low symptoms, with a difference of 2 points between groups on the DS-II considered clinically meaningful. Furthermore, discriminant validity was demonstrated, as comorbidity with depression was not observed at moderate levels of demoralization.

Conclusions: The DS-II has sound psychometric properties and is an appropriate measure of demoralization. Given its structural simplicity and brevity, it is likely to be a useful tool in meaning-centered therapies. Cancer 2016;122:2260-7. © 2016 American Cancer Society.

Keywords: cancer; construct validity; convergent validity; demoralization; discriminant validity; external validity; revalidation.