Letters to the Editor. Sizing up the PO

In a Sept. 30 article [``Strange Green folks at the post office: a practical proposal''], Rushworth Kidder cites a study on first-class mail service in the New York metropolitan area made by Congressman William Green of New York. The author concludes that an independent body is needed to measure actual first-class mail service provided by the Postal Service. An interesting proposal, but there are several points that need to be addressed. The service measurement test performed by Congressman Green is similar to the Diagnostic Service Analysis Tests (DSAT) that the Postal Service conducts. Both tests enter small volumes of mail into the mailstream and measure the time it takes for the test pieces to be delivered. Both tests are only representative of that particular mailing, not of the total mail service being given in a particular area. To measure the metropolitan service, thousands of pieces of mail would have to be mailed over an extended period at great cost. This is what the more sophisticated Origin-Destination Information System (ODIS), used by the Postal Service, does.

However, the tests that the congressman and the Postal Service conduct (DSAT) are valuable as diagnostic tools. By using the results, specific service problems within a ZIP code area can be highlighted. Further, those tests can be used to assess service trends if they are repeated several times. Using the congressman's studies as indicators of service improvement or decline, we find a 23.7 percentage point improvement in first-class mail service from 1982 to 1985. Not surprisingly, our own internal test ing procedures (ODIS) indicate service improvement of a similar magnitude, 20 percentage points over the same period of time.

Mr. Kidder's column implies that the Postal Service is independent of any public or private organization regarding its service performance. The General Accounting Office also performs service reviews and audits, which are acted upon by Postal Service management.

We recognize that there's room for improvement, but first-class mail service in New York is far better than illustrated by Congressman Green's figures. Jackie A. Strange Deputy Postmaster General Washington

Postal Service management, relying on ODIS statistics, claims 96 percent achievement of delivery standards in first-class mail. Those figures are radically different from those compiled by the monitoring service of Reader's Digest and Doubleday Inc. According to USPS figures, ODIS costs the service $47 million annually. John Crutcher Postal Rate Commission Washington