"Barbados," sighs the Jamaican economist with an expression of mixed envy and disgust, "is the goody-two-shoes of the Caribbean . . . the kid in your class who brushes his teeth . . . the one whose shoes are always shined.

"Barbados drives everybody else in the region up a wall."

In a part of the world where economic ruin is always just around the corner, where politics is an increasingly nasty business, where close historical ties among nations sometimes result in intense rivalry, this 166-square-mile patch in the eastern Caribbean is what Jimmy Carter might call an "island of stability in a sea of chaos."

Budgets are balanced in Barbados. The growth rate is usually healthy, while respectably moderate -- like a well-groomed, British businessman. The buses seem to run on time, the hedges are clipped, elections are held regularly and governments change with a ninimum of fuss.

There are reasons for all this besides serendipity, and if one neglects to ask what they are, one may well expect to be told anyway.

"Why don't you ask me about Barbados?" prompted a senior government official in an interview begun with questions on regional security problems that of late have kept the State Department awake nights.

Answering his own question, he talks of a high-caliber civil service, an ability to prevent brain drain that has afflicted Barbados' neighbors, a tough government willing to make unpopular decisions, a high component of foreign investment.

They must have been doing something right. A recent World Bank report on "current situation and prospects" of Caribbean economics is by and large a depressing litany of countries characterized as "disappointing . . . less favorable . . . zero growth." But the report perks up on the subject of Barbados.

"In 1979," it says, "the economy of Barbados repeated its strong performance of the previous year . . . growth of 6.5 percent . . . record tourist arrivals . . . growth of manufactured exports . . recovery of sugar production, and construction boom."

Other Caribbean governments and leaders, from the mercurial Eric Williams in Trinidad to the charismatic Michael Manley in Jamaica and Grenada's militant new rulers, make the region a sea of what could be described as "characters" of one sort of another, each with a strong and distinctive personality.

Not here. Prime Minister Tom Adams exudes an aura of sober governance, of subdued charm, quick intelligence and, when it seems appropriate, wit.

And when it becomes necessary to put some muscle behind the government's moderation, Barbados does not shirk. The Barbados Defense Force, resented by some neighbors and admired by others, has answered a number of calls to install order in the region, most recently by invitation of the government of St. Vincent to put down an incipient rebellion in December on the tiny Vincentian-owned Union Island.

British diplomats, noting the neatness and orderliness of Barbados' parliamentary system, its white-wigged judiciary and straight accounting columns, appeared to take a certain amount of pride in, and no small credit for the successes of their favorite Caribbean son.

A British colony for three centuries until independence in 1966, Barbados was the only Caribbean colony that never changed hands during the hundreds of years of island-shuffling between Britain and France. Nearby St. Lucia, which has had its own electoral problems recently, went back and forth between the two European colonial powers 14 times.

In a division that hardly seems possible considering its small landmass, neighboring St. Kitts once was controlled north and south by the French while "we had the middle," a British official said.

The United States and Britain have made Barbados the hub of their diplomatic activities in the eastern Caribbean, where for the past 20 years Britain has been primarily concerned with getting rid of colonies.

Two British dependences remain in the Caribbean. One of them, Antigua, is due for independence at the end of this year. As usual, there is a hitch. While Antiguans are in the middle of an island-wide argument over how, when and under what local government to make the break with Britain, the island is having trouble with its own "colony."

The small Antiguan island of Barbuda, whose entire 1,100 population survives on its lobster catch and lives in one small village, is threatening to secede from Antigua in order to stay with the British -- much to the consternation of her majesty's government.

With the tourist trade running smoothly, the sugar cane harvested and the rainy season hard upon them, Barbadians are resting easy these days. They are a self-assured people, proud of their accomplishments, conservative in their politics and concerned about correctness in their dealings with others.

For the first two weeks of this month, their attention has been absorbed by an issue that -- to the extent such things happen in the polite atmosphere here -- has aroused local passions over the eternal conflict between a conservative morality and a commitment to personal freedom.

For weeks, the front page of The Advocate News, the island's leading daily paper, and its letters to the editor column, as well as radio talk shows and cocktail party conversations, have been filled with debate on a Barbadian businessman's plan to open a nudist camp for tourists and local sun seekers.

"Why all this shame about our bodies," asked a letter writer who signed himself Theosophus. Following a long discourse on the human body as a temple of God and a lack of shame in pure nature, he concluded, "To the nudist . . . I can only say 'right on.'"

Another writer, however, pointed out that tourism has helped "corrupt the morals of our country" and that nudism would be even worse. "Let them go to Martinique," this writer suggested. He closed with the additional admonition that the local tourist board should circulate posters informing visitors of the proper dress for Bridgetown and the possibilities of fines for those who do not respect "a certain standard" in Barbados.

But there apparently is a higher standard here. Tolerance eventually won out over outrage, and the nudist camp opened on schedule.