The aim of this study was to develop a Korean version of Night Eating Questionnaire (KNEQ) and test its psychometric properties and evaluate items according to item response theory.

The 14-item NEQ as a measure of severity of the night eating syndrome was translated into Korean, and then this KNEQ was evaluated. A total of 1171 participants aged 20 to 50 completed the KNEQ on the Internet. To test reliability and validity, Cronbach's alpha, correlation, simple regression, and factor analysis were used. Each item was analyzed according to Rasch-Andrich rating scale model and item difficulty, discrimination, infit/outfit, and point measure correlation were evaluated.

Construct validity was evident. Cronbach's alpha was .78. The items of evening hyperphagia and nocturnal ingestion showed high ability in discriminating people with night eating syndrome, while items of morning anorexia and mood/sleep provided relatively little information. The results of item analysis showed that item2 and item7 needed to be revised to improve the reliability of KNEQ.

KNEQ is an appropriate instrument to measure severity of night eating syndrome with good validity and reliability. However, further studies are needed to find cut-off scores to screen persons with night eating syndrome.

The purposes of this study were to develop a Minimal Insomnia Screening Scale for Korean adults (KMISS) and to evaluate psychometric properties and discriminant ability of the developed scale.

Data from a cross-sectional survey of 959 Korean adults were analyzed to develop the summated insomnia scale, which was evaluated in terms of reliability, validity, and discriminant ability by receiver operating characteristics (ROC) curve analysis.

Item-total correlations ranged between .71-.79 and Cronbach's α was .87. Adequate validity was also evident. ROC-curve analysis showed area under ROC was .87 (95% CI: .84-.90) and identified the optimal cut-off score as ≤ 20 (sensitivity, .83; specificity, .75; positive/negative predictive values, .40/.95). Using this cut-off score, the prevalence of insomnia in the study sample was 26.3% and most frequent among women and the oldest group.

Data supports the psychometric properties of KMISS as a possible insomnia screening instrument. KMISS also shows promise as a convenient ultra-short screening measure of insomnia for adults and epidemiological studies in community health care settings.