Minneapolis LRV, a project built with New Starts before the total focus on the CEI. CC image from joelplutchak on flickr.

Following up from previous discussions of precision and accuracy, Elana Schor at Streetsblog delves deeper into the subject.

While addressing the U.S. Conference of Mayors, assistant transport secretary for policy Polly Trottenberg was asked by the mayor of Clearwater, Florida, to outline how the agency might “quantify livability” in its upcoming rulemaking.

“Not everything can be measured,” Trottenberg said, adding that her colleagues wanted to avoid making the “mistake of false precision.”

She also addressed the pitfalls of relying on in-house economic predictions to assess transit projects. Several local rail lines have quickly exceeded initial federal ridership projections, casting doubt on the models used for the so-called New Starts program.

“Sometimes we’ve gotten so tangled up in the perfect mathematical science — we did it in New Starts,” Trottenberg said.

Data is good.  But we cannot limit our information inputs to just quantitative measures.  And when we do use them, we need to understand their limits.  I’m eager to see how the FTA decides to evaluate the livability criteria, but the acknowledgment that the numbers have limits is a big step forward.