The encouraging news from the U.S. Commerce Department this week that Maine income is among the fastest growing in the nation could mean that Maine truly is on the move, leaving its 39th place in this category for higher rankings. Or it could mean something else entirely. As state policymakers sort out the data, they should celebrate the news but also get serious about understanding its source.

On their own, high growth rates are almost always better than low ones. But Maine may simply be the recipient of good fortune from a strong national economy; it may be leading growth now because it has lagged for so long and most other parts of the nation have grown as much as their workforce allows. Or it may have strong growth based on one or two projects: the state’s construction income grew 21.4 percent in 1999, the single largest jump of any category in New England. Much of that came from the construction of the natural-gas pipeline, which, of course, will not be built again. The other big gain in income came in the finance division, 18.7 percent — MBNA accounts for much of that.

This is not to suggest Maine should view the rising income numbers as anything less than positive. Taken with the rising levels of employment in every county in the state, it suggests Maine is doing substantially better economically than it has in many years. More importantly, it suggests that the greatest threat to northern Maine, the loss of people, has abated and even turned around. This is truly terrific. But it isn’t sufficient for Maine to simply pat itself on the back and say good enough.

A group of state lawmakers recently began to tour the state, describing the economic incentives for businesses they passed last session. Giving the public a more comprehensive view of the legislation, rather than the day-by-day accounts of individual bills that appear in the media, is welcome. Equally needed, however, is a review of the effects of all the years of earlier legislation. Anecdotes abound; meaningful numbers on the results of all that legislating do not.

What better time than now, during high levels of growth, to renew the state’s efforts to demonstrate what works and what doesn’t? While pipeline projects come around only once in a generation, there’s nothing to suggest that Maine can’t gather data on effective state programs and use them to continue in this positive direction. Maine could get on the move with fuel of its own making, controlling its future in a way it never has before.