Did you know that the scope of the setting of selection criteria is to ensure that a candidate or tenderer is reliable, has respective technical and professional skills as well as financial and technical ability to perform the contract to appropriate quality standards? It is strongly recommended to set criteria related and proportionate to the subject matter of the contract. Criteria, which serve the same purpose, form barriers for economic operators and reduce the number of potential suppliers. That is precisely the reason why the contracting authorities try to keep the number of the relevant evidences to a minimum.
For instance, on average the Department of Contracts of Malta sets only one, Swedish central purchasing body - two and Irish Dep. Of Finance – three tender participation requirements (Source: Dimitri N., Piga G., Spagnolo G. (2006). Handbook of Procurement).