How about conducting the U.S. census not just once every decade but twice?

If that idea sounds far-fetched, think again. A census every five years was authorized by Congress in 1976. Now the suggestion is being raised by the highly respected Congressional Quarterly.Up to a point, the proposed change makes sense. Seats in Congress are reapportioned on the basis of the census. Likewise, federal and state aid is allocated on the basis of the nose-count. So a more frequent and, consequently, more accurate population count would be fairer politically and economically.

That's why five-year censuses are conducted in Canada and Australia.

Don't mention a more frequent count to the U.S. Census Bureau, however. The bureau is all but overwhelmed by the burdens of doing the decennial census. Just the thought of a more frequent count prompts talk of mass hara-kiri around the bureau.

Besides, the change might double the cost of the count. As it is now, the tab - which exceeded $1 billion in 1980 - came to $2 billion in 1990 and is expected to far exceed $3 billion by the turn of the century.

But one reason for the escalating cost is that the census-takers are being ordered to count more and more than just population numbers. They also are required to gather data on Americans' income, age, marital status, race, citizenship, ancestry, education, language, military service, disability and transportation habits - among other things.

Though such information is useful, it's not always essential. So how about switching from the 10-year schedule to a five-year census but alternating between the present, full-scale count and a streamlined version that tallies only population figures and nothing else?

As matters now stand, the census is stuck in a rut. The very least Washington should do is to rethink this big, costly operation.