I cannot count how many times a columnist or reporter from out of town has ridden into the big city to report to the naive back home how he got taken for a $10 hamburger and how nasty New Yorkers didn't curtsy as he ambled down Broadway. Recently, the Miami Herald produced a comic version of this kind of reportage, but that was more a satiric swipe at The New York Times for a Sunday magazine cover story about poor old Miami.

It's more serious when a newspaper with the reputation of The Washington Post assigns a correspondent to write a three-part series on New York. The series appeared in late August and focused on economic development, the South Bronx and municipal corruption. Much old and bad news was reported, but the series contained little of the events that are transforming the city.

The fact that New York City's economy is booming is obvious to even the most casual observer. What is less apparent, certainly to Washington Post readers, is that the city's recovery has not been limited to Manhattan.

One of the latest additions to the city's skyline is the new operations center of the financial giant Morgan Stanley -- a building not on Wall Street, but on "Wall Street East" in downtown Brooklyn. British Airways has a new headquarters with more than 700 workers -- in Jackson Heights, Queens. Merrill Lynch announced a move of its capital-markets operations out of Manhattan to Staten Island's Teleport. And Bathgate Industrial Park has state-of-the-art businesses, ranging from high-speed printing to pharmaceuticals to an indoor herb farm -- all in the South Bronx.

In fact, since 1984, in percentage terms the Bronx, Brooklyn, Queens and Staten Island have had higher job growth than Manhattan. All five boroughs have gained jobs. In the last three years the Bronx has gained 14,900 jobs, Brooklyn 13,300, Staten Island 3,000 and Queens 28,200. For The Post, these numbers don't exist.

Our economic development efforts are also having positive effects on the employment picture for blacks and Hispanics. According to the U.S. Bureau of Labor Statistics, during the first half of 1987 the unemployment rate for blacks in the city was 9.3 percent, compared with a national rate of 13.7 percent. During the same period Hispanic unemployment here was 8.7 percent, compared with 9.5 percent nationally. While these levels are still too high, they do underscore the fact that the city's economic strength has benefited large groups of New Yorkers.

It is easy to point to blight in the South Bronx and say, "There it is," but nowhere in the reporting is the news that the decline has stopped. Nor have "ideas for urban redemption run out," as The Post said. Sections of neighborhoods have been reclaimed, building by building, and now, under new programs -- including 929 units in the Construction Management Program -- block by block. More and more, landlords in tax arrears are not abandoning buildings -- they are coming back and paying up.

Progress is not as visible as decline. Gut rehabilitation cannot be seen from the outside, but since 1984, 4,000 apartments have been renovated for homeless families, and another 3,378 units are being or are about to be rehabilitated.

Reading the series left me with a terrible taste in my mouth. The reporter would have you believe that the prosperity of the 1980s has produced a corruption problem that permeates the city administration and all other branches of local government, as well as state government and Wall Street. Even worse, the Post reporter would have you believe that nobody cares enough to do anything about it.

I am not going to take issue with the conclusion that we have a corruption problem. We do, and I am not in a position to defend entities other than my own administration. But with only six people from this administration either indicted or convicted, it is just not fair to impugn the integrity of their 300,000 fellow employees.

The writer attempts to imply that I have spent more of my time on self-promotion than in tending to the city's needs. The article offers no factual basis for this conclusion.

Evidence to the contrary is all around us -- for all those who will but see.

Edward Koch

The writer is mayor of New York City.