Abstract

Unbalanced bidding is a widely used practice in competitive bidding and is often associated with unit price contracts. This practice has attracted the attention of researchers for more than seventy years due to its impacts on the owner and the contractor. This paper presents the results of a survey targeting construction contractors in Jordan to ascertain the root causes of this practice, common forms of unbalanced bidding, owner’s prevention strategies to mitigate this practice, and detection methods for unbalanced bidding. The study indicated that discrepancies in the owner-provided quantities of work and the utilization of unit pricing for items that are difficult to estimate their quantities accurately are the most enabling circumstances for unbalanced bidding. The study also revealed that the most common types of unbalancing bids in the Jordanian construction industry are front-end loading and increasing the unit prices of items that have underestimated quantities while simultaneously decreasing the prices of items that have overestimated quantities. The survey respondents indicated that the top-ranking strategies that owners can utilize to reduce the extent of this practice are ensuring accurate estimating of quantities in the bill of quantities, and timely processing of progress payments. The findings of this study are beneficial to both owners and contractors. Owners will be better aware of the current utilization of unbalanced bidding by contractors and can improve bidding rules and instructions to mitigate this practice. Contractors will also have a better understanding of their competitors' utilization of the imbalance in their submitted bids.