Most economic reports should come with a warning: the data is subject to revision. Today’s glowing number that’s the toast of the punditocracy is tomorrow’s statistical detritus. But if the world is always eager to move on to the next number du jour, and forget yesterday’s news, informed analysts recognize that monitoring the initial estimates of a data series, and tracking its path through time, offers another layer of intelligence. For example, a recent study by the Philadelphia Fed found a “small positive (but statistically significant) association between the revision to job gains and the level of job gains.”