Abstract
Bid rigging — the collusive manipulation of competitive tendering processes by ostensibly independent bidders — remained one of the most economically damaging and difficult-to-detect forms of procurement fraud. Unlike bribery or embezzlement, bid rigging often leaved few direct documentary traces, since the manipulation occurred through coordination among external parties who each submitted facially legitimate bids. This paper presented a comprehensive review of bid rigging detection mechanisms and their associated economic impacts. It examined the principal forms of bid rigging, including cover bidding, bid suppression, bid rotation, and subcontracting arrangements, and evaluated the quantitative and qualitative detection methodologies used by competition authorities and procurement agencies, including price-and-cost screens, statistical bid-pattern analysis, market structure screens, and behavioural and digital forensic indicators. The paper then assessed the economic consequences of bid rigging, drawing on empirical estimates of price overcharges, allocative inefficiency, reduced innovation incentives, and the fiscal burden imposed on public procurement budgets. The analysis found that while quantitative screening tools had substantially improved ex-post detection capability, their effectiveness depended heavily on data availability, market structure knowledge, and complementary legal and institutional enforcement capacity. The paper concluded that a layered detection strategy — combining statistical screens, whistleblower mechanisms, leniency programmes, and market structure monitoring — offered the most robust defence against bid rigging, and it proposed policy recommendations for strengthening detection capacity, particularly in developing and transitional economies.