Psychometric Properties of the Need to Belong Scale based on classical test theory and Item-response

The purpose of the present study was to investigate the factor structure and Item-Response parameters of the Need to Belong Scale (NTBS) in students. The research design was a descriptive-correlation and validation study. The statistical population consisted of undergraduate and master's students of Birjand University. In two studies, 164 and 236 of these students were selected by multi-stage cluster sampling. Data collected by the Need to Belong Scale (NTBS; Kelly, 1999), the Social and Emotional Loneliness Scale for Adults (SELSA-S; Ditommaso, et al., 2004), Depression, Anxiety, Stress Scale (DASS; Lovibond, & Lovibond, 1995), Basic Need Satisfaction in Relationships (BNS-RS; LaGuardia, et al, 2000) and the Satisfaction with Life Scale (SWLS; Diener, et al, 1985). Internal consistency, exploratory and confirmatory factor analysis, discrimination and threshold parameters, and Item and test information curves were analyzed. Results showed that the Need to Belong Scale shows the structure of an agent with an explained variance of 67.87%. Confirmatory validity was confirmed. Cronbach's alpha coefficients for the scales varied from 0.95 to 0.91 and split-half coefficients varied from 0.94 to 0.89, respectively. The Item-Response parameters were also at the optimum level (P<0.05). It seems that the Need to Belong Scale has good reliability and validity in students.