From a backlog, an inside story:

Under the headline "Reagan Pressures Israelis for Withdrawal Schedule" (front page, Dec. 17), the lead paragraph said: "President Reagan tried to increase the pressure on Israel yesterday to agree to a timetable for withdrawing its troops from Lebanon, saying 'the time is now for action.'" The story was based on an interview Post reporters had with Mr. Reagan Dec. 16.

The headline and lead were consistent. But neither was supported by anything the president actually said, and that was further demonstrated two days later when The Post ran a full transcript of the interview.

Commenting on Lebanon's right to sovereignty, Mr. Reagan calls on "Syria, Israel and the remnants of the PLO . . . to get out," but does not identify Israel separately.

Readers who questioned the story's validity overlooked (if they got that far) two sentences in the 14th paragraph: "Reagan's appeal for withdrawal was cast in general terms in order not to undercut the negotiations . . . but U.S. officials readily acknowledged that the president had Israel in mind . . . ." Reporter Lou Cannon, it turns out, was advised that, however stated, this was the message Mr. Reagan intended. It was indicated also that this would be the substance of a letter his negotiators would carry to Israel and was consistent with what reporters were being told elsewhere in the administration.

All this may have been evident to foreign affairs aficionados who read between the lines, but what about the average reader, for whom newspapers are supposed to be written? It isn't as easy for them to bridge the gap between what's said and what's intended. Readers would have been better served by moving up that 14th paragraph.

Also in the backlog:

The American-Arab Anti-Discrimination Committee protested a second time recently the publication of maps Jan. 2 that neglected to delimit the disputed status of East Jerusalem. Similar maps were published last April. An AAADC letter stated "that Israel's annexation of the environs of East Jerusalem is not recognized by any nation in the world . . . . Only Israeli maps of the West Bank include the annexation to the north, east and south of Jerusalem as part of pre-'67 Israel." It is true that official U.S. maps have not changed the 1967 boundaries as they affect Jerusalem, the West Bank, Golan Heights and Gaza.

The Post was in error and was not attempting a political statement with the maps. Steps have been taken, cartographers and editors promise, to ensure that it won't happen again.

Abscam: Post readers still have not had the last word on the Senate's review of FBI conduct during the "sting" that led to convictions of seven members of Congress. In early December, the paper ran a Los Angeles Times story based on the special Senate panel's draft report, then ignored its official release two weeks later. Even the Times updated its story to take account, among other things, of the committee's recommendations for stricter legislative guidelines for investigations, clarification of federal law on entrapment and compensation for innocent victims in "sting" operations.

Having done extensive reporting of Abscam disclosures and trials, The Post seemed curiously content to leave the final chapter to another newspaper.

Doonesbury: By the time he took a vacation from his Pulitzer Prize-winning comic strip recently, Garry Trudeau was already the subject of extensive news coverage. The normally "low- profile" artist's background and future plans were outlined in a lengthy front- page Style article New Year's Day.

It is only coincidence that Mr. Trudeau came into the news when area members of the National Federation of Parents for Drug Free Youth were trying to interest Post editors in their cause--more particularly in their perceived adversary, the National Organization for Reform of Marijuana Laws. NORML advocates legalization of marijuana. Parents for Drug Free Youth contend that organization seeks "ultimate legalization of all drugs."

Mr. Trudeau supports NORML, having offered original Doonesbury strips and other artwork for its profit. His syndicate, Universal Features, has confirmed this. For the record, this information might well have been included in the New Year's Day feature.