A public body must award to the lowest responsive and responsible bidder, and rejecting a low bidder as not responsible requires more process than rejecting one as non-responsive.
Responsiveness concerns the bid: does it conform to the solicitation in all material respects. Determined from the bid documents, and a non-responsive bid is rejected without a hearing.
Responsibility concerns the bidder: capacity, experience, financial resources, equipment, personnel, integrity and record of performance. Because a finding of non-responsibility reflects on the bidder’s business reputation, due process in many jurisdictions requires notice of the grounds and an opportunity to respond before rejection.
The record. Findings supported by evidence — performance history documented, references contacted and recorded, financial information reviewed. A rejection based on a general reputation or on an official’s impression is reversed.
Prequalification systems address this in advance and are the better approach where the work is specialised, provided the criteria are objective and published and there is an appeal.
Debarment is a separate and more serious determination, requiring a formal process, and it is present-responsibility based rather than punitive.
Documentation retained, because the file is what defends the award against a protest.