1. a Division of Management , Caledonian Business School , Glasgow Caledonian University , Cowcaddens, Glasgow G4 0JF, UK
2. b Centre for Research in Six Sigma and Process Improvement (CRISSPI) , Caledonian Business School , Glasgow Caledonian University , Cowcaddens, Glasgow G4 0BA, UK
3. c Department of Production Engineering , Birla Institute of Technology , Mesra, Ranchi-835 215, India
4. d Department of Forge Technology , National Institute of Foundry and Forge Technology , Ranchi-834 003, India