Job growth in several outer suburbs of Washington was among the strongest in the nation in the year ended in March, the Labor Department reported last week. But in the same report, the department provided evidence that some of the strongest growth in wages in the Washington area is in closer-in areas.

Loudoun County had exceptionally strong wage growth, said the Labor Department -- a 10.1 percent climb to $979 a week, fifth in the U.S. in percentage gain.

But Loudoun was the exception to the rule. The other local jurisdictions where wages were climbing strongly were Arlington County, where they rose 8.7 percent to $1,240 a week, Montgomery County, where wages rose 7.8 percent to $1,014 per week, and the District, where wages rose 7.2 percent to $1,221 per week. Arlington, Montgomery, and the District were ranked, respectively, 7th, 11th, and 15th in the nation in wage gains.

Other outer suburbs added jobs at a faster pace than their close-in neighbors, but generally wages there climbed at a more measured rate -- 2.2 percent in Prince William County, for example, and 3.3 percent in Howard County.

The reason may have to do with a shift in the types of jobs that are located in the three close-in jurisdictions. One possible explanation is that low- to moderate-wage jobs could be disproportionately in outer suburbs, while new jobs in pricey inner suburbs are disproportionately those that have high wages, thus raising the averages.

-- Neil Irwin