Two recent comments on different topics got me thinking about averages, and why people like to talk about them more than they like hearing about them.
Toronto transit expert Steve Munro made this comment on the familiar perils of transit operations in that city:
In Toronto, the TTC reports that routes have average loads on vehicles, and that these fit within standards, without disclosing the range of values, or even attempting any estimate of the latent demand the route is not handling because of undependable service. Service actually has been cut on routes where the “averages” look just fine, but the quality of service on the street is terrible. Some of the planning staff understand that extra capacity can be provided by running properly spaced and managed service, but a cultural divide between planning and operations gets in the way.