Sometimes counting souls doesn't add up.

What's the fastest-growing religion in the United States? Islam? The Church of Scientology? Mormonism? Jehovah's Witnesses? How about the Church of God in Christ? Or the Armenian Apostolic Church? Every few months someone in the media nominates a new candidate for the honor.

Recently both CNN and CBS told viewers that Islam had become the fastest-growing religion in the country. Last year the Gannett News Service published a chart that indicated that there were "at least 5 million Muslims" in America. A few years earlier the New York Times put the figure at 6 million. If either the Gannett or Times figures were correct, Islam would probably win the title.

Now two sociologists, Barry Kosmin and Seymour Lachman, have published the findings of the National Survey of Religious Identification (NSRI) in their new book, One Nation Under God. The City University of New York professors directed this 1990 survey, the largest by far of any such undertaking and one that claims a sampling error of less than 1 percent. They contacted 113,000 people over the age of 18 in the contiguous states and came up with the figure of only 527,000 Muslims. Even this figure had been adjusted upward to compensate for any possible undercount.

Certainly immigration, large families, and conversions, especially within the African American community, have greatly increased the number of Muslims in the U.S., but with only 527,000 adults identifying themselves as Muslims, this religion has a long way to go to qualify as the fastest growing. (The NSRI survey showed, rather surprisingly, that most Arab Americans call themselves Christians rather than Muslims.)

Here is another candidate. The head of the controversial Church of Scientology told Larry King on his CNN talk show in late 1993 that his church now counted 8 million members worldwide, making it the fastest-growing religion in the world. Scientologists claim that 4,500,000 of these members live in the U.S. Since this church had not been formed until 1954, perhaps it would be a contender for best performance.

But in its famous cover story on Scientology in 1991, Time magazine had noted "Scientology probably has about 50,000 active members, far fewer than the 8 million the group claims." This much lower figure was confirmed by the NSRI, which estimated 45,000 adult Scientologists in the 48 continental states. The Church of Scientology seems to have multiplied its active membership by a factor of 100.

For many religion writers the Yearbook of American and Canadian Churches has been a standard reference work on membership statistics. In the 1993 edition two writers in the Yearbook call the Church of God in Christ, a predominantly black, Pentecostal body, "the fastest-growing major denomination in the 1990s." The Yearbook lists this church with 5,499,875 members. A long feature article in the Chicago Tribune provided wider dissemination of this information. Fifteen years ago the Church of God in Christ reported only 425,000 members. Its twelvefold increase since then would clearly entitle it to the fastest-growing title, right? Not quite. Again, the NSRI of 113,000 adults discovered only 14 people who identified themselves as members of the Church of God in Christ, and from this the statisticians extrapolated a total membership of only 32,000.

Ever hear of the Armenian Apostolic Church? The 1993 Yearbook compares membership growth of American churches between 1980 and 1990 and reported that this church experienced an amazing 619 percent growth during this decade. No other church came close. But the size of the Armenian Apostolic Church--25,000 full communicants--hardly cuts it into the major denomination category.

During this same period the Roman Catholic Church grew 12.4 percent, the Southern Baptist Convention 16.3 percent, and the Mormon Church 31.9 percent. Many mainline Protestant churches, such as the Episcopal, Presbyterian (USA), United Church of Christ, and the United Methodist, lost members.

No one doubts that two American-born religious bodies have registered impressive growth in recent years. With 40,000 full-time missionaries in the field, the Church of Jesus Christ of Latter-day Saints--the Mormons--has baptized as many as 300,000 adult converts in a single year. In 25 years its worldwide membership has tripled, and it now claims 4,250,000 adherents in the U.S. alone. Another sect that aggressively seeks converts by knocking on doors, Jehovah's Witnesses, reports 914,000 members in this country, but the NSRI estimates an even larger constituency: 1,381,000 adult Witnesses.

Using Yearbook figures Time magazine reported last year that the Church of God in Cleveland, Tennessee grew faster than any other church between 1965 and 1989. In these years it registered a 183 percent increase to 582,200 members. Obviously these various rankings depend on the time period chosen for comparison. Equally obvious is that a small church can post an impressive gain and remain quite inconspicuous on the national scene. For example, a body with 10,000 communicants could grow five-fold and be unknown to the average American.

Anyone seeking to understand religion in U.S. life will want to base his or her conclusions on the best available statistics. Otherwise the observer is likely to come up with a distortion rather than a reflection of reality. For example, the role of Islam in the U.S. will be seen in quite a different light if we believe there are about 527,000 Muslims rather than 6 million.

Certainly other areas of society lend themselves to misunderstandings: some people say the homeless number no more than 300,000 while others talk about 2 million. Based on Kinsey studies of prison populations, journalists write about a homosexual percentage of 10 percent while recent studies suggest the figure may be closer to 1 or 2 percent. So religious preference is hardly the only area of statistical disagreements, but it is one that can be refined with the help of sociological surveys and common sense.

We might ask why some churches grow while others stagnate or lose members. Roger Finke, a sociologist of religion at Purdue University and co-author of The Churching of America 1776 to 1990 (Rutgers University Press, 1993), notes: "From Congregationalists to Catholics many religious groups have experienced their most rapid growth when they offer a vivid sense of otherworldliness, stress a distinctive lifestyle, place clear demands on the membership, and generate a religious subculture that mirrors that of the dominant culture." Adds Finke: "High fertility rates, immigration, and aggressive marketing all fuel this growth, but the religion's intense faith and distinctive subculture retain the faithful."

Whether a church is growing or shrinking, the many conflicting claims, surveys, and journalistic reports demonstrate the difficulty in counting souls with any accuracy. The figures submitted by some church officials are clearly unreliable. The methods of counting members will vary: some churches tally all baptized members; some baptize at four weeks; and others delay initiation until the age of 13 or 14. A few count only confirmed members.

You call them Catholic?

The problem with counting souls is well illustrated by the question "Who is a Catholic?" Is it someone who meets the definition of canon law: a baptized person who has not apostatized or joined another church? Or is it someone who is not only baptized but observes the laws of the church by attending Mass every Sunday and holy day of obligation, fasting and abstaining on appointed days, contributing to the support of the church, and so on? Or is a Catholic anyone who says he or she is a Catholic?

Most Catholic pastors are inclined to adopt a rather restrictive definition since they must forward an annual contribution to the local bishop based on the number of parishioners. These pastors may be reluctant to claim individuals who never darken the church doors. This is one reason why the number of Americans who identify themselves as Roman Catholics always far exceeds the official tally of the Catholic population.

If membership in particular denominations is hard to determine, so is the number of such groups. In the preface to James LeBar's book Cults, Sects, and the New Age (Our Sunday Visitor, 1989), Cardinal John O'Connor of New York writes: "In the past decade alone, more than 2,500 'new' religious cults have appeared in the United States." Most scholars would recognize J. Gordon Melton as the dean of American religious encyclopedists. He compiled the Encyclopedic Handbook of Cults in America, as well as the three-volume Encyclopedia of American Religions. While the cardinal refers to 2,500 cults, Melton estimates there are no more than 500 to 600 such groups in this country, and many of these go back to the early years of this century.

Toward the end of World War II the Navy sent me to Oklahoma A & M to study Japanese. I soon discovered that the state of Oklahoma was dry. I also discovered that two disparate groups were especially intent on keeping the state dry: the Baptists and the bootleggers. Each had its own reasons.

Likewise we find that two opposing groups tend to exaggerate the strength of religious cults: the leaders of the cults and the anticult activists. The cultists like to provide inflated membership figures to the media to enhance their power and prestige. The anticultists do the same thing to create fear and sell books, tapes, and memberships in their organizations.

For example, before the massacre in Guyana the Rev. Jim Jones used to boast that he had 200,000 followers. After 912 people were murdered or committed suicide in the Peoples Temple compound, the public found out that the deceased comprised most of Jones' cult. Some popular writers, evangelical and Catholic, suggest that millions of unsuspecting Americans are being lured into thousands of cults. Melton estimates no more than 200,000 people belong to 20th-century cults such as the Moonies and Hare Krishnas.

Yet another phenomenon--phantom churches--complicates the counting process. Several decades ago, while writing a book on American denominations, I came across a group called the Christ Unity Science Church. The Yearbook reported it had 1,500,000 members. Repeated attempts to contact officials of this church by mail and phone failed. Finally I dropped a note to the editors of the Yearbook suggesting they investigate whether this body even existed and, if so, whether it enrolled this many communicants. Apparently they did check it out because the next year's edition dropped the Christ Unity Science Church altogether. (The "loss" of 1,500,000 Protestants in a single year drew some editorial comment from religious publishers.)

Swedish equals Lutheran

The problem with counting souls also extends beyond U.S. borders. Using figures from the Statistical Yearbook of the Church and the Annuario Pontificio, the Catholic Almanac reports the percentage of Roman Catholics in nations around the world. Does anyone really believe that 97.9 percent of Italians are Catholic when using any real definition of the term? That would mean that only 2.1 percent of the population of Italy is made up of atheists and agnostics, Jews, Muslims, Protestants, and other non-Catholics.

Nor is it reasonable to accept that 94.9 percent of Spaniards and 88 percent of Brazilians belong in the Catholic category. Millions of these folks were carried into church by their parents and godparents at Baptism and have not been seen there since. Likewise almost all of the 8,500,000 people in Sweden are counted as Lutherans. Everyone in that country is automatically enrolled in the Lutheran Church at birth and remains on the rolls unless the individual takes steps to disassociate himself or herself from the state church; most people don't bother.

The accuracy of denominational statistics in the U.S. would be immeasurably improved if a question on religion were included in the federal census. The last time this was done was in 1936. Some civil-rights organizations and religious groups objected to the religious question even if it were voluntary, and it has not been asked since.

Without census data we are left with sociological samplings and statistics furnished by denominational headquarters. The estimates for the larger denominations and families of churches are probably on target. The Roman Catholic Church, which had only about 25,000 adherents among the 3 million people in the original 13 colonies, has become the largest church in the nation. It counts almost 60 million members (46 million over the age of 18 according to the NSRI). Members of the various Baptist churches form the next largest religious grouping, followed by the Methodists, Lutherans, and Presbyterians. Problems surface when we try to estimate the membership of the smaller and newer religious bodies, and the strength of the cults is certainly exaggerated.

So all in all we should take these membership estimates not with a grain but a fistful of salt. Next time you come across a statistic on church membership, say, "That's nice, but who's counting?"