The total hours of interviews were split up between interviewing purchasing personnel on site of the case company and interviewing suppliers that interacted closely with the case company, which has also been recently mentioned as raising the validity and reliability of such inter-organisational studies, as such a method allows multi-perspectival analysis (Frankel et al., 2005). The former interviews were primarily conducted with a large portion of the strategic purchasers and a smaller part of the interviews were conducted with the heads of the purchasing division