This study addressed a perceived research gap by examining the role of performance feedback in construction process performance from both client and contractor perspectives using a database of unprecedented scale, with 2,175 sets of observations (expressed views of 579 clients and 1,596 contractors involved in diverse Swedish construction projects). Following validation of latent concepts by multigroup assessment of responses across the two groups (clients and contractors), using confirmatory factor analysis, this enabled robust tests of evidence of structural paths (potentially causal or mediating relationships) embedded in both groups’ responses. The results confirmed, with unprecedented clarity, that performance feedback has significant, direct positive effects on construction process performance, and that performance feedback mediates (i.e., strengthens) effects of learning and collaboration on process performance.