They are called the yordim, and they are at once loathed and envied in a land whose very purpose is rooted in fealty to the Zionist dream.

They show up in the cavernous departure terminal at Ben Gurion International Airport, clutching tourist visas to faraway places -- more often than not to the United States. But the overflowing baggage carts they wheel through the crowds suggest something longer than just a scenic tour or a visit with friends and relatives.

Some of them obviously are of limited means, headed for a job driving a taxi in the unfamiliar streets of Manhattan. Some carry in a single pocket a large but inconspicuous financial stake in expensive diamonds bought with proceeds from the sale of an apartment or car.

But most also leave with a self-comforting rationalization that someday they will return and the the Jewish sanctuary, whose government says it is so dependent upon them, will be none the worse for their departure.

The yordim, or emigrants, leave behind them in the land of Zion a troubled nation, one beset by mind-boggling inflation, scarce and expensive housing, high taxes, the relentless threat of war, constant internal political bickering and demands for self-sacrifice surpassed by few countries in the world.

They also leave behind a growing -- and misleading -- controversy about their own decisions to laredet (descend), an especially deprecating term because immigration, or aliya (ascending), is the highest call of Zionism. b

The controversy is misleading because the figures for emigration are deceiving, and often distorted by alarmists, sometimes for transparently political reasons, and sometimes because Israelis tend to be more obsessed with their perceived failures than with their successes.

Isrealis are leaving Israel, and they have since the Jewish state was founded on May 15, 1948. Yet the same Yordim are also returning in large numbers, and emigration in both real terms and in proportion to the natural population growth, is actually declining, according to the most authoritative statistics available.

True to the adage that "Figures don't lie, but liars figure," demographers and statisticians are at loggerheads over what the real numbers of emigrants are. This is partly because the statistical data available is insufficient for empirically determining who is an emigrant and who has merely gone aboard for an indefinite length of time without declaring any intentions to stay or return.

Apparently based largely on estimation and extrapolation, and partly on supposition, a parliamentary committee recently caused a minor panic by declaring that as many as 25,000 Israelis are expected to immigrate this year, and warning that if the trend continues more Jews will soon be departing than arriving from other countries.

This set off a national debate over issues no less weighty than the viability of the Zionist ideal, the future security of the stae and the alleged damage caused by Prime Minister Menachem Begin's controversial economic and foreign policies.

"Last one out should turn out the lights, already," went the dark humor of some fainthearted. The more serious doubters wondered aloud whether Israel, inured to war for three decades, could actually cope with peace.

Sitting in the living room of a comfortable but cramped apartment in Neytanya, about 25 miles north of Tel Aviv along the Mediterrean coast, Gideon and Nili Asherie reflected on their decision to leave Israel 10 years ago.

Asherie was fresh out of Tel Aviv University with a degree in economics, a 25-year-old veteran of the 1967 Arab-Israeli war, but jobless and with few immediate prospects for a fulfilling career. His attractive and outgoing wife had finished law school and was ready to "see what was going on somewhere else in the world."

Making a conscious decision to emigrate from Israel would have been an anathema to Asherie. He is a sabra, a fourth-generation Israeli whose father and grandfather were both born in the Jewish quarter of the ancient Old City of Jerusalem.

So Asherie left for New York on a student visa, assuring skeptical friends that he had not been seduced by the lure of American comforts but would return when he completed his master's degree at New York University and, maybe, worked a while in America for the experience.

The Asheries, just married and childless then, bought one-way tickets and stamped through customs control at Ben Gurion airport, became potential yordim in the computers at the government's central bureau of statistics, housed in a row of drab grey buildings in the Foreign Ministry complex in Jersualem.

Do you know arithmetic?" asks David Neumann, who has worked for the Central Bureau of Statistics. "Then take the total number of residents who have left Israel since May 15, 1948, and subtract the total number who have returned. That, my friend, is the yordim everyone is arguing about, almost."

According to the bureau's data, 3,977,000 residents left the country between 1948 and 1979, and 3,640,000 returned, leaving 337,000 still abroad. Parliament's immigration committee, without explaining the discrepancy, estimated 400,000 Israelis are living in the United States alone.

Because the 337,000 figure includes Israelis who at the end of 1979 went abroad and have not had time to return if they are students or extended tourists, the bureau estimates that the number of potential permanent emigrants is 300,000.

An emigrant, by government definition, is someone who traveled abroad and who has not, or will not, return within four years, which is the period of passport exiration. The government, sidestepping the onerous connotations of the question, does not ask departing Israeli travelers whether they intend to return.

Last year, Neumann said, there were 10,000 emigrants, or, more precisely, 10,000 Israelis living abroad who were statistically lumped into the category of "residents abroad who have not returned in four years." This is 5,000 less than estimated by the parliamentary committee.

Based on statistical trends, Neumann said, "1980 may turn out to be one of the lowest years ever" for emigration.

Paradoxically, the reason for that is because immigration has been declining, with 11,750 immigrants arriving in Israel during the first six months of this year, compared to 17,723 in the first half of 1979. The decline reflects, for the most part, a sharp decline in the number of immigrants from the Soviet Union.

Because any year's group of immigration includes a large number of potential dropouts, Neumann said immigration and emigration cannot be viewed as mutually exclusive. This is particularly true of Soviet immigrants, who often find life in Israel more difficult that they expected and re-emigrate to the United States.

Neumann also suggested that the turmoil in Iran, including reported persecution of Iranian Jews, may have a psychological effect on immigration. "It reinforces the belief that Israel is the one safe refuge for Jews," he said.

After graduating from New York University graduate business school, Gideon Asherie decided to take a job with a New York-based shipping firm and gain some marketing management experience. The Asheries began having children -- three were born in America -- and they moved into a small rented home in suburban Larchmont, N.Y.

Life became comfortable, the Asheries remember. Their children were in good Westchester County schools, they enjoyed the ambience of suburban America and the pay was good at Asherie's job in the World Trade Center.

"Container shipping was becoming big and I was learning a new technology. I became a New York addict. It's like a bug, it grows on you -- the theater, the crowds. America is so great, you can't compare it with Israel, Italy, or anywhere. It is the United States, and then there is the rest of the world," Asherie said.

The Asherie's children grew up learning English. Gideon and Nili made American friends and became involved in local Jewish community affairs and settled into Larchmont life. They laughed at the local rabbis' annual public outrage over the placing of a Christmas creche at the village hall, and unashamedly enjoyed the warmth and hospitality of their new neighbors.

"We lived very nicely. We didn't save a lot of money, but we enjoyed the life. We enjoyed all the things a middle class family can afford there, but can't seem to afford in Israel. There you could buy a good book for $10, and think nothing of it. In Israel, a book for 500 pounds is a big expense," Asherie said.

"We didn't forget being Israelis. Being Jewish and being Israeli still was a large part of our lives. There was a great awareness of it in our house. But we were starting to get pretty comfortable in Larchmont," he added.

If there is a typical Israeli emigrant, according to the Bureau of Statistics, he or she is a 25- to 35-year-old, native-born sabra whose parents immigrated from Europe or the United States. Single, secular, living in a large city here and middle or upper middle class, these are the other characteristics of the normal yordim.

"The poor don't leave because they can't afford it, and the very rich don't leave because they can't afford to, either. The very young don't leave because the army has its hands on them, and the very old don't leave because their roots are too deep. Unfortunately, that leaves the people Israel needs to keep most," Neumann said.

Trying to profile the motives of emigration may be a frivolous exericise at best, because yordim don't go around announcing their intentions.

The economy is certainly a factor, although inflation tends to hurt institutions and the nation as a whole more than it hurts individuals, because salaries and wages are linked to the cost of living index. A few may be driven away by a military obligation that keeps Israeli men in the service until age 55, and a few may be frightened by the constant threat of war.

Anye Dulzin, chairman of the Jewish Agency, believes the biggest cause of emigration is housing, and that the phenomenon won't cease until Israel stops being a land of apartment ownership.

"We have to set more rental housing, or we're not going to keep young couples who can't afford modest apartments that sell at inflated prices of $100,000 or more," Dulzin said in an interview.

Another factor may be as basic as the historic transitory tradition of Jews, who were forced for ages to pick up and move, acquiring the characteristics of the "wandering Jew."

Whatever the cause, many Israelis are beginning to conclude that the effect has been exaggerated. They point out that since 1948 there was only one year -- 1953, when postwar austerity was severe and many European refugees returned home -- when more Jews left Israel than arrived.

(Emigration peaked, but did not surpass immigration, after the 1973 Yom Kippur War, because many Jews came here to fight and then returned to their homes abroad).

In July, 1979, Gideon and Nili Asherie decided to come back.

"We realized that if we stayed any longer, we would never come back," says Asherie, who is now a marketing executive for the Israeli Zim Shipping Lines.

"As much as we loved America, as comfortable as we were in Larchmont, Israel was the place where we belonged. We were not refugees from Israel. Israel was in my system. There is a feeling about the homeland and being Jewish, and that is what brought us back," Asherie said.

The Asheries said their friends were dumbfounded.

"They said, 'Are you crazy? Haven't you been reading the papers?' said Nili Asherie.

She had read the papers, and she was reminded more directly early on, she recalled, that there are good reasons some people leave. A year after applying for a telephone in their tiny apartment, the Asheries are still waiting.

"But we can live without the phone," Asherie quickly adds. "Other people will leave Israel, and, frankly, I wish them all the best. But we came back, and it wasn't because we were looking for a telephone or bigger television screen."