Fastest Growing Religion: Islam or Christianity?

State of World Evangelism

(Image from Mission Frontiers)

Yesterday's post left us all hanging, twisting in the wind of changes, and that gets tiresome after a while . . . especially as the noose begins to tighten.

You'll recall that we were wondering about the data in this paragraph:

In fact, and perhaps counterintuitively, the number of new Christians each year outstrips the number of new Muslims, even though the annual growth rate is higher for Muslims (1.81 percent) than for Christians (1.23 percent). Over the last century, Christians have grown at a slower rate than have Muslims, with Muslims increasing from 12 percent to 21 percent of the global population during that time. But this is hardly surprising. Christianity has more total followers than Islam. More people need to become Christians annually simply to remain at roughly a third of the world population. Muslims are increasing in sub-Saharan Africa and among African Americans by conversion, but elsewhere the growth is mostly by birth or immigration. The major growth for Protestants, especially evangelicals and Pentecostals, has been by conversion. (J. Dudley Woodberry, Russell G. Shubin, and G. Marks, "Why Muslims Follow Jesus: The results of a recent survey of converts from Islam," Christianity Today, October 2007)

In posting this yesterday, I noted that the article neglects to provide the sources and that I hadn't been able to locate any sources online (though I know that I've seen such statistics previously).

After posting my entry, I recalled that the article states that readers can request copies of the questionnaire from Professor Woodberry, so I wondered if sources for the statistics are also available, and I wrote him an email explaining my request:

"I tried to Google the statistical information on Christian and Muslim growth rates but failed to locate the statistics. Could you direct me to the online statistics that support this passage."

Professor Woodberry replied:

The manuscript I submitted to Christianity Today included a footnote documenting the statistics, but the publishers did not include it in the published version. The footnote reads: David B. Barrett, Todd M. Johnson, and Peter Crossing, "The Status of Global Mission, Presence and Activities, AD 1800-2025," International Bulletin of Missionary Research, 31, no. 1 (Jan. 2007), 32; Patrick Johnstone, Operation World (Grand Rapids, MI: Zondervan, 1993), 159, 183, 319, 431.

With this information, I've found both sources . . . sort of. The International Bulletin of Missionary Research (IBMR) is online, but not all of its articles. One can visit the website and even see the editorial for January 2007, but the article itself is closed except to subscribers, so I can't check it myself. I'd really like to be able to do so, for the title differs from the one that Professor Woodberry graciously supplied. Here's what I found listed in the table of contents to IBMR's January 2007 issue:

"Missiometrics 2007: Creating Your Own Analysis of Global Data," David B. Barrett, Todd M. Johnson, and Peter F. Crossing.

This appears to go from page 25 to page 32, and Woodberry cites page 32, so this must be the right article. I'm therefore assuming that Woodberry provided me (and Christianity Today) with the heading for a chart labeled "The Status of Global Mission, Presence and Activities, AD 1800-2025" but forgot to include the article title. That sort of oversight can easily happen, and I'm sure that I've often done the same. I've emailed Professor Woodberry again for clarification.

As for the other citation, to Patrick Johnstone's book, Operation World, I've found the book listed on Amazon.com, but the 1993 Zondervan edition appears to be out of print. A 1995 edition put out by O. M. Literature seems to be in print, however. Any readers with access can look there and report back at leisure...

Meanwhile, one could do some browsing at a couple of online sites mentioned in the IBMR's editorial for January 2007. The World Christian Database would be a great online resource, but one needs a subscription to access the relevant data there. The other link, to the Sydney Centre for World Mission, is more helpful, for it can lead to either of two useful places, depending upon what one clicks: "Status of global mission" or "Visual status".

Browse around and see what you find...

Islam: The 'Fastest-Growing' Religion?

Relative Proportion of Christianity to Islam?

(Image from Wikipedia)

We hear a lot about Islam being "the fastest-growing religion," but fastest in what sense is usually left unsaid. Islam cannot be the fastest growing in terms of percentage if compared to all religions, for some new religion with a handful of adherents might be growing by 1000 percent annually if it starts with the founder and increases in one year to 10 persons.

Indeed, I could start a new religion myself, and the growth from 0 to 1 would be statistically off the charts for the first year . . . though the growth for its second year would likely level off to, oh, about none at all.

Anyway, I think that the statement about Islam's increase can only be correct if the major world religions are being compared. But even so, does "fastest-growing" refer to percentage or to absolute numbers? And does the growth come from population expansion or from conversion?

I get all sorts of mailings in my online quest to know everything, and the following information from J. Dudley Woodberry, Russell G. Shubin, and G. Marks came just yesterday via Christianity Today:

In fact, and perhaps counterintuitively, the number of new Christians each year outstrips the number of new Muslims, even though the annual growth rate is higher for Muslims (1.81 percent) than for Christians (1.23 percent). Over the last century, Christians have grown at a slower rate than have Muslims, with Muslims increasing from 12 percent to 21 percent of the global population during that time. But this is hardly surprising. Christianity has more total followers than Islam. More people need to become Christians annually simply to remain at roughly a third of the world population. Muslims are increasing in sub-Saharan Africa and among African Americans by conversion, but elsewhere the growth is mostly by birth or immigration. The major growth for Protestants, especially evangelicals and Pentecostals, has been by conversion.

The article in which this passage occurs is titled "Why Muslims Follow Jesus: The results of a recent survey of converts from Islam" (Christianity Today, October 2007). The survey is thus only a survey of converts, specifically, 750 Muslims converts to Christianity from 30 countries and 50 ethnic groups; it is not a survey of conversion rates generally.

The information in the passage above comes from a different study that the article neglects to link to and that I haven't quickly located online though I know that I've seen it before.

At any rate -- or, actually, not at any rate -- Islam would appear to be the fastest-growing major religion if one means percentage increase, but not the fastest-growing if one means absolute increase.

Most interesting was the statement that this growth comes mostly from population expansion, not from conversion, which suggests that Islam is not actually a very popular choice among religions to convert to.

I'd like to see the hard statistics, however, and do wish that the article had linked to them.