Detecting abnormal and collusive bids in capped tendering

Recent developments in the area of Bid Tender Forecasting have enabled bidders to implement new types of easy-to-use tools for increasing their chances of winning contracts. Although these new tools (such as iso-Score Curve Graphs, Scoring Probability Graphs, and Position Probability Graphs) are designed for bidders in capped tendering (tenders with an upper price limit), some of their principles can also be applied by a Contracting Authority to detect which bidders do not follow a standard pattern, that is, their bids are extremely high or low. Since a collusive bid generally needs to be sufficiently high or low to make an impact on the bid distribution, any person in charge of supervising capped tenders can be alerted to any bidder that might be involved in a cartel after identifying the same abnormal behavior in a series of tenders through simple calculations and a new type of graph.

► New application of the Ballesteros-Pérez et al. (2012) bid tender forecasting model. ► Easy method for detecting abnormally high or low bids in capped tendering. ► Standard Drop Graph (SDG) enables tender managers to detect collusive bids. ► New conception of bidders' bids distribution in capped tendering.