In public procurement, byers typically try to resolve the problem of not knowing the tenders before stating their preferences through the use of price relative models or comparison prices and different procurements use slightly different spreadsheet models for tender evaluation. This renders it difficult to assess the quality attributes in a way enabling for evaluating and comparing price-quality properties of real-life tender evaluations. However, tender evaluation is an instance of multi-attribute decision-making, and for each tender evaluation instance there is a corresponding multi-attribute decision model enabling for a more systematic assessment of tender evaluations. In this paper, we investigate how robust the selection of tenders in IT procurement are towards changes in the assessment of quality and to the presence of quality attributes in the tender evaluation model. Conclusions include that "decisive"attributes cannot be expected to exist, and that score based tender evaluation model with precise estimates of quality levels put strong demands on the capabilities of the buyer.