Downtown development in Baltimore, while considerable, lags behind construction activity in Washington by almost any measure.

Although the cities are neighbors and often mentioned in the same breath, authorities stress that any comparison between a blue-collar industrial city and the nation's capital will be an apples and oranges situation.

For example, eight hotels that opened this year or are under construction will double the number of hotel rooms in Baltimore, to about 4,300, with about 3,500 in its suburbs. In the District, a dozen new or restored hotels, including the 744-room J.W. Marriott, will have opened in the same period. The District has about 20,000 hotel rooms, plus another 20,000 in its suburbs.

In recent years, overall commercial construction in the District, the third largest office market in the United States, has outstripped that in Baltimore by about 4 to 1.

What can be compared, according to M. Jay Brodie, a planner who has worked in both cities, are efforts to rebuild Baltimore's Inner Harbor and Washington's Pennsylvania Avenue.

Brodie, executive director of the Pennsylvania Avenue Development Corp., said it has been nearly as difficult to attract investors, and public interest, to the revitalization of Pennsylvania Avenue as it was to fix up Baltimore's Inner Harbor. Both required "a degree of marketing to change perceptions," he said. "Developers didn't want to invest and people didn't want to come there."