Abstract
Changes almost always occur on construction projects. Among other things, they can hurt labor productivity. The relationship between change and labor productivity, though commonly acknowledged, is not well understood. In this paper, such causal linkages are illustrated to capture the interactions of changes, disruptions, productivity losses, and the responsible parties. They go an extra step from the current mechanism of changes, disruptions, and inefficiency to underline the critical role of causing parties in cumulative impacts. From these causal linkages it is visible that: (1) even when disruptions are initially caused by one party (e.g., the owner), the other party (e.g., the contractor) may be able to reduce or escalate the disruptions and inefficiency throughout the course of work; and (2) productivity losses rarely result from a single causing factor but multiple and concurrent ones for which both parties can be responsible. Also, the methods available for quantifying lost productivity are systemized in this paper to visualize relationships among uncertainty, effort and expertise to use, and the level of contemporaneous project documentation required of these methods. A conceptual framework is also proposed herein to help project participants match the relevant quantifying analysis with their project circumstances.