Through much of the twentieth century, it was widely believed among Western intellectuals that the Chinese were immune to religion”an immunity that long preceded the communist rise to power. When, in 1934, Edgar Snow quipped that “in China, opium is the religion of the people,” many academic and media experts smiled in agreement and dismissed the million Chinese claimed as converts by Christian missionaries as nothing but “rice Christians””cynical souls who had frequented the missions for the benefits they provided. Then, in 1949, Mao Zedong came to power. Religion was outlawed, and it was widely agreed among social scientists that China soon would be a model of the fully secularized, post-religious society.

But it wasn’t to be. Instead, belief in a coming post-religious China turned out to be the opium of Western intellectuals. The Chinese Christians of 1949”those ridiculed in the West as rice Christians”were so “insincere” that they endured decades of bloody repression during which their numbers grew. And as official repression has weakened, Christianity has been growing at an astonishing rate in China.

Unfortunately, there is a great deal of disagreement over just how astonishing the growth has been: Are there now 16 million or 200 million Christians in China? Both numbers have been asserted with great confidence and with claims of being “official,” but perhaps the most widely accepted claim is that there are 130 million Chinese Christians. That total is often attributed to a survey conducted by the Chinese government. But it seems unlikely that there was such a poll”at least no Chinese scholars and polling agencies know of it”and that total is not supported by any of the known surveys. Some of the confusion may arise from the fact that the Chinese government does keep track of how many people belong to Christian groups officially registered under the terms of the Three-Self Patriotic Movement (TSPM). These groups now enroll about 16 million members. But there are tens of thousands of Christian house churches in China that are not registered with the TSPM. Not surprisingly, there is considerable interest among diverse groups in learning how many members these house churches have. Estimates have been based not on solid data but rather on intuition and anecdotal accounts of largely Western observers.

At last it is possible to make a relatively accurate estimate of the total number of Christians in China. Our starting point is a national survey of China conducted in 2007 by Horizon, Ltd., one of China’s largest and most respected polling firms. It is based on a national multistage probability sample of Chinese in mainland China. Respondents had to be sixteen or older, have lived at their current residence for three months, and not been part of a survey in the past six months. The survey involved face-to-face interviews conducted by a regular staff of trained interviewers”Horizon does frequent surveys. Respondents were chosen by using a multistage method to select metropolitan cities, towns, and administrative villages. The final survey was administered in fifty-six locales throughout China, including three municipal cities (Beijing, Shanghai, Chongqing) and six province capital cities (Guangzhou, Nanjing, Wuhan, Hefei, Xi’an, and Chengdu). In addition, eleven regional level cities, sixteen small towns, and twenty administrative villages were sampled. Within each locale, households were sampled within neighborhoods, and neighborhoods were sampled within administratively defined total neighborhood committees (government-defined collections of neighborhoods). A grid procedure was used to randomly select one respondent from each household for a face-to-face in-home interview. In all, 7021 Chinese were interviewed.

These data have been made available to the Institute for Studies of Religion at Baylor University by means of a generous grant from the John Templeton Foundation.

Of these 7021 Chinese respondents, in 2007 3.1 percent of Chinese indicated they were Christians (2.9 percent Protestants and 0.2 percent Catholics). Based on these data, one can argue for a total of 35.3 million Chinese Christians over the age of sixteen.

But for several reasons we know this total is substantially too low. Many Chinese refuse to participate in survey studies, and it is assumed that Christians are unusually likely to do so”it remains somewhat risky for Chinese to be identified as Christians. In addition, some Christians who do agree to be interviewed are likely to think it unwise to admit being a Christian when asked that question by a stranger. To get an accurate estimate of the number of Chinese Christians requires a correction factor for both of these suppressors.

To address these concerns we launched a follow-up study in cooperation with colleagues at Peking University in Beijing. Based on contacts in the Chinese Christian community, we were able to obtain samples of members of Chinese house churches from many of the same areas used in the original survey sample. Survey interviewers were sent to seek interviews with these people, all of whom were active Christians (though this was unknown to the interviewers). Of these known Christians, 62 percent refused to be interviewed compared with an overall refusal rate of 38 percent for the original survey. Adjusting for this difference in response rates yields an estimate of 58.9 million Christians sixteen and older.

In addition, of those known Christians who did agree to be interviewed, 9 percent did not admit to being Christians when asked. Correcting for that suppressor brings the number of Christian Chinese sixteen and older to 64.3 million. Of course, this total is for 2007. Obviously the total is higher now. It seems entirely credible to estimate that there are about 70 million Chinese Christians in 2011.

We do not know how people have arrived at the estimates of 200 million Christians in China. We have not been able to uncover one article, story, or reference that includes an estimate with an accompanying explanation”let alone an estimate that provides a sound research methodology and appropriate scientific rigor. It would appear that so-called experts have simply repeated unsubstantiated figures they have heard from others.

Beyond this important finding, the survey also makes it possible to gain some insights into who is converting to Christianity. As is consistent with all religious groups around the world, Chinese women are almost twice as apt to be Christians as are men. Not surprisingly, no current member of the Communist Party confessed to being a Christian, although 1.7 percent of those belonging to the Communist Youth League did so.

Some suppose that older people are more apt to have become Christians, while others believe that the elderly cling to tradition and that it is young people who are converting. But the survey data show that age has no significant effect. It is widely believed that Christianity has stronger roots in the rural areas than in the cities, but the data do not support this claim. In addition, when Chinese are separated according to where they grew up (lived until age fifteen), no significant differences emerge.

Contrary to standard sociological wisdom, some observers have suggested that Christianity is spreading more rapidly among the more privileged Chinese. In fact, the data support that view: When Communist Party and Youth League members are excluded (since they are clustered among those with higher incomes), the higher their income, the more likely Chinese are to be Christians.

Of course, even if Chinese Christians total 70 million, they still make up only slightly more than 5 percent of the population, although they are about as numerous as are members of the Chinese Communist Party. Thus, it may be vital for the safety of the Christian community that Christians are clustered among the more affluent and are not concentrated in rural areas. Indeed, American visitors to leading Chinese universities are struck by the Christian climate that often prevails in contrast even with most American church-supported campuses. Despite many years of dramatic religious persecution, we now have empirical evidence of the resiliency of Christianity in China and the remarkable trajectory of growth it continues to experience.

Rodney Stark and Byron Johnson are distinguished professors of the social sciences and Carson Mencken is professor of sociology at Baylor University.