Not only is it common courtesy to tell unsuccessful bidders why they have not been selected, for many organisations it is also essential to provide a debrief.
When someone has gone to a great deal of effort to win the bid and produce a high quality tender document that gets them through to the tender shortlist presentation, then telling them why they didn’t win the contract makes all parties feel good.
• It provides a learning curve for the teams that didn’t win.
• It shows your organisation in a professional light, as many don’t even think to provide feedback.
• It encourages the best suppliers to tender for your business as word gets out that you are fair and do give a damn!
Keep the emotion out of it by issuing a polite letter to the unsuccessful bidders: this should contain the debrief information with a form showing how they scored against the evaluation criteria, alongside the same for the winner.
That may be sufficient but if they want more (give your name and contact details to show willing) your objectivity should avoid any argument and you will be seen to be helping them for future bids.