Planning times for commercial real-estate projects—from the hiring of an architect to draw up preliminary plans to the start of construction—across the United States are long and getting longer, research conducted by Jonathan N. Millar of the Federal Reserve Board, Stephen D. Oliner of the UCLA Ziman Center for Real Estate and the American Enterprise Institute, and Daniel E. Sichel of Wellesley College indicates.

Analyzing roughly 82,000 projects for which planning was initiated between 1999 and 2010, the researchers found the average planning time to be about 17 months and that planning times had increased by three to four months over the course of the sample period.

The “heat map” below shows differences in planning times, in months, across metropolitan areas. For a condensed analysis of the study, as well as a link to download the working paper, go to http://bit.ly/planning_times.