Some U.S. diplomats in Central America are concerned about what they see as a widening gap between their reporting and Washington's policy toward the area.

The diplomats say they are particularly worried about what they perceive as a tendency of the senior decision-makers to force what is often inconclusive and possibly misleading information to match the policy rather than tailoring the policy to the facts.

There is little disagreement with the administration's basic policy of keeping Soviet-aligned Communists from taking power anywhere in the area. At the same time, it is commonplace to find differences of opinion between Washington and virtually any of its embassies around the world given the different audiences and pressures each set of officials must confront.

But as the battle for El Salvador and the region grows more costly and more dangerous to the region as a whole, the concern expressed by half a dozen experienced diplomats at different levels of the embassy hierarchy here, and some senior diplomats in other Latin American posts, is that Washington may be acting on the basis of wishful thinking rather than solid facts.

"In order to justify policy you make propaganda and interpret facts to justify a position. That's fine," one diplomat here said. "Now the question is, are we making policy on the basis of our own propaganda? Is the information tainted by our own view?"

The answer, this diplomat and some others concluded is, "Yes, absolutely."

While this is certainly not a unanimous conclusion, there is widespread acknowledgement, especially in the San Salvador embassy, that the basic reporting on local military and political events is often seriously, unavoidably flawed.

As controversy over U.S. policy here has grown, the debate has in part become centered on the relative reliability of wildly conflicting accounts--from the various governments interested or involved, from the warring military camps, from nongovernmental figures with vested interests, from the media--of what is going on in El Salvador. Here, those who express the least certainty frequently are those who are most concerned about objectivity and aware of their own limitations in gathering information.

"I'll tell you what the problem with our embassy reporting is," said a senior diplomat here. "It's full of doubts. We say this guy does this or that. But we don't know. We don't get out to see."

Over the past year, the fighting in El Salvador's civil war has moved out of San Salvador, leaving the capital in relative peace. But major confrontations occur in the countryside, and the diplomats in this beleaguered, understaffed embassy are mostly trapped behind its sandbagged walls by both their workload and security considerations.

At the moment there are only two embassy staffers, both of them relatively junior, who regularly get out into the countryside. Both of them frequently do so on their own initiative and occasionally without prior clearance.

But one diplomat here admitted bluntly, "I don't want to go out; I want to survive."

A striking example of the way resulting gaps in information spin out in Washington appeared in the congressional testimony of Assistant Secretary of State Thomas O. Enders early last month.

Enders stated that "we sent two embassy officers to investigate recent reports of a massacre in the Morazan village in El Mozote. They reported that . . . no evidence could be found to confirm that government forces systematically massacred civilians in the operation zone, nor that the number of civilians killed even remotely approached the 733 or 926 victims variously cited in press reports."

Enders clearly implied that the two embassy officials sent to investigate the case actually got there, looked around and reached the conclusion he cited.

According to embassy officials here, however, the usual two field men were not able to get closer to the scene than three miles away and only saw El Mozote from 2,000 feet in the air, when their helicopter was fired on.

Later, despite the basic conclusion of the report that "something god-awful" happened at El Mozote, as U.S. Ambassador Deane R. Hinton put it, no deaths from the incident were ever recorded in the embassy's regular weekly violence statistics. The administration has based much of its public case for an improving human rights record here on this "grim-gram" that computes and attributes political killings on the basis of highly unreliable local press reports.

On the crucial question of arms flow from Nicaragua to Salvadoran rebels, which has been cited repeatedly as the cause for much of the administration's hostility toward the Sandinista government in Managua, embassy officials all over the region say they have no concrete idea of how much trafficking is actually taking place.

Such evidence of extensive arms shipments as exists is said to come from high-technology intelligence to which even some senior diplomats do not have effective access.

Embassy staffers here say that the tendency toward what they feel are errors in perception and judgment in Washington is probably heightened as diplomats are encouraged to report raw data as if it were fact, in some cases regardless of the source.

In one example mentioned by several diplomats here, the Salvadoran vice president, Gen. Jaime Abdul Gutierrez, dismissed press reports of a "death squad" dumping ground at the El Playon lava beds east of the capital as a "press invention."

This seemingly authoritative statement by a high-ranking official initially was relayed to Washington without caveats, even though top government officials here are known for obfuscation on such questions, which are particularly embarrassing since the death squads often are linked to government forces.

On this occasion an embassy staffer was able to go to El Playon, saw the bodies, and the record was set straight.

As one frustrated embassy staffer in El Salvador put his concern, "Massive amounts of information are being sent to Washington, but all that really doesn't change how the policy goes."