Chamorro Losing Ground in Nicaragua : Polls: Three opinion surveys give President Ortega a huge advantage. Some observers question methods in polling.

President Daniel Ortega’s chief rival in the Feb. 25 election has lost ground in all five voter opinion polls published in recent weeks, and three of the surveys give the Sandinista leader a huge advantage.

Violeta Barrios de Chamorro, the challenger, is ahead by smaller margins in the other two polls, conducted for her United Nicaraguan Opposition (UNO). But those results are questioned by independent analysts because their polling methods have not been fully disclosed.

The disparity between voter preference figures in the two sets of surveys is so wide, surpassing all margins of statistical error, that analysts warn against relying on any of them to predict the election outcome. A “poll war,” they say, has shed more heat than light on the campaign.

But there is no question that Chamorro was in a slump in January, when the latest polls were taken.

Her campaign manager, Antonio Lacayo, acknowledged the unfavorable trend in an interview last week. But he insisted that it was momentary and caused by a downturn of opposition campaign activity, which has been revived in the last two weeks by large and enthusiastic crowds at Chamorro’s rallies.

Ortega led Chamorro 53% to 35% in a survey by the Washington pollsters Bendixen & Schroth broadcast recently by Univision, a Miami-based, Spanish-language television network. Univision’s previous poll, in October, put Ortega up by one point, 40% to 39%.

Two polls done by another Washington firm, Greenberg-Lake, for a Boston-based election observer group called Hemisphere Initiatives, show voter preference for Ortega rising to 51% in January from 44% in December, while Chamorro remained stuck at 27%.

Similarly, with the challenger static at 18%, Ortega soared from 36% to 54% between October and January, according to surveys done for the Jesuit-run Central American University here by ECO, a Nicaraguan company that often polls for the government.

Chamorro’s own surveys, by Costa Rican pollster Victor Borge, show her ahead. But her lead slipped sharply, from 44% to 18% in October to 37% to 30% in January.

Doxa, a Venezuelan company also polling for the opposition, gave Chamorro a 36% to 25% edge in December, which was cut slightly last month, from 41% to 33%.

Chamorro’s campaign manager said the polls were taken after her campaign hit a low point in early January. Its funds were running short then, and a broken kneecap sidelined the candidate for 18 days, while the Ortega campaign was in full stride.

But most pollsters, including her own, say Chamorro was hurt on the issues as well. They said the U.S. invasion of Panama and increased military activity by the Contras, who are highly unpopular among Nicaraguans, helped Ortega shift attention from his weakest issue, the shattered economy.

“The only way to explain the shift is the war and peace issue,” said Sergio Bendixen, the Univision poll director. “Feelings about the war run deep, and once such an emotional issue takes over, it is hard to turn the campaign around.”

The Bendixen poll is significant because its fieldwork was conducted by Logos, the only Nicaraguan polling firm regarded by both camps as relatively neutral.

Since opinion polling was first permitted here in June, 1988, eight companies have published 21 surveys and interviewed more than 36,000 of Nicaragua’s 1.7 million registered voters.

“This is obviously the most surveyed Third World country,” said William Bollinger, director of the Inter-American Research Center in Los Angeles. “The problem is that polling is still so new here, there is a lot of potential for biased results.”