MacLeamy's time-effort distribution curves are among the most oft-cited sources for researchers interested in mainstreaming building information modeling (BIM) implementation in the architecture, engineering, and construction (AEC) industry. Succinctly, the curves offer a clever answer to the question: How can BIM benefit AEC processes? However, despite their significant theoretical and practical value, little previous research has been conducted to elaborate the time-effort distribution curves of any real-life projects. This research aims to demystify the time-effort distribution curves through comparison of a representative BIM project and a non-BIM project. Applying a set of innovative approaches, the actual time-effort distribution curves of two public housing construction projects in Hong Kong are produced and analyzed in-depth. The curves vividly show that BIM implementation increases the effort spent at design stage-that is, throughout the architecture and engineering processes-but the extra effort pays off at the building stage. Further, the curves are found to be a useful graphical analytic tool for other purposes, such as adjusting the fee structure among AEC processes and informing improved BIM adoption. (C) 2015 American Society of Civil Engineers.