Photo by RHiNO NEAL on Flickr.

There’s a lot of wiggle room in how WMATA reports Metro’s on-time performance. We need something more accurate.

Periodically, Metro reports its on-time performance to both the public and the WMATA board. In 2014, more than 90% of Metrorail trains were “on time.”

But Metro doesn’t arrive at those numbers in a way that makes sense for passengers, and its practices can lead to counterproductive moves like intentionally delaying trains to cook the books.

Metro counts a train as “on time” if it arrives somewhere close to within the scheduled headway, which is the block of time that passes between trains. During rush periods, the headway plus or minus two minutes counts, and during off-peak periods, it’s one-and-a-half headways.

That means that when a lead train starts to slow down, Metro can slow down the trains behind it and still count them as being on time. There is no measurement that tracks how fast a train moves through the system. Besides how often trains break down, the only thing reflected in Metro’s public data is the spacing between trains.

Also, only the trains that actually stop at a station are included in Metro’s on-time performance data. Metro’s reporting doesn’t include trains that go out of service or skip stations.

There are more honest ways to report Metrorail performance

Metro needs a performance standard that reflects what’s best for customers.

One way to achieve that would be to divide the amount of times a train stopped at a given station by the number of times Metro said one would stop there. This number would show all the service Metro hadn’t delivered. If Metro said 20 trains would stop at a station during rush hour and only 15 did, that’s a problem we should know about.

Another idea would be to use Smartrip data to track how many people got to their destination within a reasonable time. Metro publishes typical travel times for each possible trip. Going from Ballston to Eastern Market, for example, should take about 26 minutes.

After factoring in a reasonable walking time to and from faregates, along with time for transferring trains if necessary, Metro could report the percentage of customers who got between stations in the time Metro said it would take. This would emphasize the delays that happen when customers can’t get on a train, have to offload, or are on trains that travel slowly.

Metro needs to improve its customer reputation. Honest performance metrics, even if they aren’t particularly flattering, would be a good place to start.