The throughput effect of Traffic Management Advisor (TMA) metering for Los Angeles International Airport was estimated with censored regression. Under TMA metering, traffic management coordinators receive advisories about when individual flights should be scheduled to enter the terminal area, accounting for the unimpeded time and constraints related to separation requirements and capacity constraints. Tests of TMA metering at Los Angeles began in spring 2002; mandatory use during the morning peak period started in November 2002. This analysis focuses on observed counts during periods when metering is and is not in effect and takes into account other relevant factors such as weather, visibility, and demand. Demand is used as a censoring variable that places an upper limit on the observed count. A significant increase in achievable arrival throughput under instrument conditions was found in the morning peak period, but a significant decrease was observed under visual conditions. These results are consistent with field reports, which suggest that under visual meteorological conditions, TMA was assigning unnecessary metering delays. The success of the censored regression methodology in capturing these effects suggests that it would be useful for various other applications in which the effect of some event on airport capacity must be ascertained.