As has been mentioned above, the general selection of a vendor for a given supply is probably considered in the planning phases of a project, but not finalized until the execution phase. However, no matter who the vendor is, they do need to be qualified according to the quality system. This is something I am currently experiencing first hand at my place of employment. We are currently in the process of qualifying a new vendor for one of our principle raw materials. This was brought on due to inconsistencies in the product we were receiving from our current vendor. There are multiple teams working on this qualification, including processing/manufacturing, R&D, and regulatory. As a member of the R&D team, my contribution to this process involves validating the products performance. All that being said, the choice of vendor is something that can occur at any phase of a project, including when a project has been completed.