. Organisational commitment was measured by the nine-item version of Porter's organisational commitment scale (Porter et al., 1974; Mowday et al., 1979). This scale was used because of its reliability and validity (Mowday et al., 1979), and its widespread use and acceptance (Morris et al., 1993). A five-point Likert scale was used and individual scores were calculated by averaging the responses to the items (α = 0.86).