Validity and reliability of the Turkish version of the Glasgow Sleep Effort Scale.

OBJECTIVE: We aimed to assess the validity and reliability of a Turkish adaptation of the Glasgow Sleep Effort Scale (GSES).

METHODS: We randomly divided the data into two: one set (n = 374) was used for exploratory factor analysis (EFA) and the other (n = 373) for confirmatory factor analysis (CFA). The psychometric properties were assessed using the item response theory approach. Reliability analyses were assessed. Convergent validity of the GSES with the Dysfunctional Beliefs and Attitudes About Sleep Scale-16 (DBAS-16), Pittsburgh Sleep Quality Index (PSQI), Insomnia Severity Index (ISI), and Depression Anxiety Stress Scale-21 (DASS-21) were explored. For the predictive validity, we used an independent-samples t-test for comparing the total score of the GSES between poor sleepers and good sleepers following the PSQI, and between clinical insomnia and non-clinical insomnia groups according to the ISI. The cut-off score of the GSES was examined.

RESULTS: A single factor structure explaining 49.2% of the total variance was detected using the EFA. The CFA also found single-factor good fit indices. Cronbach's alpha and omega values were 0.82 and 0.83, respectively. There were statistically significant correlations between the GSES and DBAS-16, ISI, PSQI, and DASS-21 in convergent validity. In the Graded Response Model, the GSES was more efficient and provided reasonable information at the -0.75 to 2.25 theta level. The GSES cut-off score was 6 points for clinical insomnia and 3 points for poor sleepers.

CONCLUSIONS: The GSES is valid and reliable for measuring sleep effort among Turkish university students.