AbstractThe resolution of claims for loss of productivity can be one of the most controversial and challenging areas in construction projects. The challenges usually come from labor productivity’s susceptibility to many factors, either within the contractor’s control or beyond its control; the difficulties in tracking loss of productivity contemporaneously; and the resulting uncertainty in proving the lost productivity attributable to the responsible parties. These challenges remain in international projects in the context of the International Federation of Consulting Engineers (FIDIC) contracts, even though these forms of contracts originated more than 60 years ago and have been widely used internationally. In particular, entitlement, causation, and credible quantification for loss of productivity claims are difficult to establish. This paper will discuss the issues of entitlement, causation, and quantification related to loss of productivity claims in the context of various FIDIC contracts along with practical considerations related to their resolutions. The intent is to help contractors, owners/employers, consultants, and other parties step through a logical process for reaching a reasonable resolution for loss of productivity claims in the context of FIDIC contracts.