The “Belbin” team role inventory: Reinterpreting reliability estimates

Previous research into the reliability of the “Belbin” team role self-perception inventory has concluded that internal consistency reliability is poor, raising concerns about the validity of the inventory as a selection and development tool. This paper argues that, in overcoming the problem of unequal scale lengths between respondents, researchers have tampered with the true error variance contained within item response sets, leading to a misapplication of Cronbach's alpha in this case. Using weighted average inter-item correlation coefficients in a formula unrelated to scale length, alternative estimates of the internal consistency reliability of the TRSPI's scales are derived. For a large data set (n=5,003), results show that the internal consistency of item responses is better than previous research suggests and tends towards the boundary at which internal consistency is considered acceptable in social and psychological research.