Since the 19th century, publications have been required to reveal their ownership in a United States Postal Service report. Since 1960, that report has had to include information about circulation, too.

Monday (Oct. 7), the Union-Tribune printed its postal service report...in small type. The results may shock some readers and advertisers. Average seven-day paid circulation for the year through Sept. 15, 2013 was only 189,822. Circulation on the filing day (Sunday, Sept. 15) was 251,318.

This report represented a stark disparity from the numbers for the six months ended March 31 released by the Alliance for Audited Media earlier this year. That report showed Monday-Friday circulation was 250,678. Sunday circulation was 409,796. I tried to contact four U-T executives, explaining that while the postal service and Alliance numbers were not strictly apples to apples, or pristinely comparable, the disparity was startling.

About half an hour ago, I received an explanation from the U-T's George Bonaros. He said of the heftier Alliance report, "This statement includes total paid print circulation, digital copies, and branded editions that make up the U-T's 'Total Average Circulation' per [Alliance] guidelines." Bonaros says that the March 31 Alliance report Monday-Friday paid print circulation was 190,892 and Sunday 287,026. He claims these numbers are comparable to the postal service report, but I would say they reveal significant deterioration since March 31.

The Alliance, formerly the Audit Bureau of Circulations, has in recent years loosened its standards so much that journalists such as myself complain that the figures are questionable. (For example, the Alliance counts a paper sold for a penny as paid circulation. The U-T separately reported in the postal service account that it distributed 7,055 daily and 10,156 Sunday, Sept. 15 editions that were free or sold for a nominal amount.)

The lesson is clear: in assessing the U-T's circulation, read the fine print -- as reported to the U.S. Postal Service.