*(An updated version of this article is available here, which includes the latest numbers from the Mormon church’s 2013 year-end statistical report.)*

I’m kind of a stats geek and I have to admit, I have a real fascination with parsing LDS Church (Mormon) self-reported statistical figures.

Just last month the LDS Church released their statistical report for 2012 at their General Conference held in Salt Lake City. They release these reports every spring, and you can review the historical data (and check my numbers) from the LDS General Conference archive here. Since the General Conference archive only goes back to 1971 (which includes 1970 data) we’ll only to analyze data from 1970 onward.

In this post I’ll analyze these numbers and see what information we can pull from the data. It’s important to note that these figures are self-reported by the LDS Church and, as far as I know, the figures are not audited or verified by any third party. The information they choose to release, accurate or inaccurate as it may be, is all that’s available. Everything else is just guesswork, and I’ll do some of that later on just for fun in a later post.

**Total LDS Church Membership**

First let’s look at the self-reported total membership of the LDS Church over time.

There’s some strong growth here. The LDS Church grew from about 3 million members in 1970 to about 15 million in 2012, which means it grew five times larger in a little more than 40 years. The graph appears to show some exponential growth, but the trend has also been quite linear since about 1990 or so.

Okay, so what about year-over-year change in membership? To get this information, I simply calculated the difference in total church membership for each consecutive year. Nothing else was taken into account. Here’s the graph.

On average, it’s obvious that the LDS Church is adding an increasing number of members each year although it’s a pretty erratic graph. Let’s smooth things out by graphing this data as a five-year rolling average.

It’s much easier to see now. There’s still an upward trend in year-over-year change in membership since 1970, but there’s also a notable downward trend since the peak in the early 1990s. To be clear, this doesn’t mean that the LDS church is not growing (the first graph proves that) but that the number of members *added* each year is down from its peak 20 years ago.

So all this is showing growth trends in terms of members added, but what happens when we look at growth trends as growth rate?

This next graph shows the percentage of year-over-year change in membership compared to the total number of members, which is effectively the church rate of growth. Again, we’re not being specific about anything other than the change in year-over-year membership. It could be due to missionary work or 8-year-old baptisms, but this data is completely neutral.

We’re seeing a downward trend, but again it’s pretty erratic so let’s smooth it out with a 5-year rolling average.

Over the past 40 years, the year-over-year rate of growth for the LDS church has been slowing. This is to be expected because it’s easier for a small organization to display huge growth rates than it is for a large one. There are a number of reasons for this, but a big reason is that each year, it’s more and more likely that receptive converts have already joined the church.

Still, the LDS Church’s current growth rate of about 2.25% well outpaces the world population growth rate of 1.15% and the United States’ population growth rate of 0.72%. This means that, if the growth rate held firm, every person in the world would eventually be a member of the LDS Church. This is highly unlikely though, given the steady, predictable erosion of the LDS Church’s growth rate. However it’s worth noting that, at the current growth rate, each year a (slightly) larger percentage of the world’s population belongs to the LDS Church. With about 6,973,700,000 people on earth, that means 0.21% of them are Mormon, or about 1 in 472. By next year, another 0.0045% of the world will probably be Mormon. Modest no doubt, but growing nonetheless.

**Missionary Work**

Evangelism is important in the LDS Church and their pursuit of new members is a proportionally gigantic effort. They have released self-reported conversion statistics as part of their annual reports since at least 1970, so we can take a peek at how the missionary effort is progressing.

First let’s take a look at total yearly convert baptisms, which means conversions coming from outside the LDS Church, and not children of church members. These are straightforward numbers, and no retention information is included here. Here’s the graph.

This convert baptisms graph generally corresponds with trends we’ve seen in previous graphs. Numbers of annual convert baptisms exploded from about 1974 until 1980, and again from 1985 until 1990. Since 1990 the trend has generally tapered downward with an obvious low spot in the mid-2000s. It has somewhat recovered in the past few years, but the current number of annual baptisms still falls short of the rates seen during the 1990s.

Now let’s look at those same convert baptisms figures as a percentage of total reported church membership. Take a look.

When looking at the growth rate of convert baptisms we see a definite downward trend. The recurring peak in the early 1990s appears here too, but an even higher peak happens in 1980, showing just how effective, proportionally, the Mormon missionary effort was from the late 1970s until the early 1980s.

Another way of saying this is that each year, it’s probable that a smaller percentage of Mormons will be new converts than in previous years. This is pretty easily shown on a graph. In any given year, a certain percentage of Mormons will have been baptized within the past five years and we can display this trend, year by year, with this graph.

Over time, new converts are becoming rarer in the Mormon church. In 1980 nearly 1/5 of all members had been baptized within the previous five years. By 1990 the number had fallen to about 1/6, and in 2012 fewer than 1/10 of members had been baptized within the past five years. The opposite is true too; more than 90% of all current LDS church members have been Mormon for over five years (92.3%).

**Children of Record and 8-Year-Old Baptisms**

In the LDS church, children are eligible for baptism when they turn eight years old. For statistical purposes the church has historically separated convert baptisms from child baptisms, probably to differentiate growth from missionary work versus growth from natural population growth.

There’s some statistical trouble here though because the LDS church hasn’t always counted growth from reproduction the same way through the years. In 1970, which is our statistical starting year for this study, the LDS church reported the number of 8-year-old baptisms as well as the number of children of record. I assume these two numbers show the number of children added to the official member tally (8-year-old baptisms) and the number of new babies which were blessed but not added to the membership tally (children of record). This reporting changed for 1984 when the LDS church began reporting only 8-year-old baptisms and stopped reporting children of record. This continued until 1997 when the reporting reversed, and the church started reporting children of record and not specifically 8-year-old baptisms. This reporting continues from 1997 forward. It’s unclear whether the church merely changed the title of the statistic, or if they actually began counting a different set of people. We don’t know so we won’t assume that we know what’s going on. For our purposes here we’ll only look at the numbers.

To reflect these statistical inconsistencies I’ll need to show more than one line on the next graph. One line (green) shows the number of children of record, while the other line (blue) shows the number of 8-year-olds baptized. Here’s what it looks like.

To be really honest, I don’t know what’s going on. There’s no way to be certain. There are a few things we can gather, however. First, things are trending upward for both metrics indicating that there are more children in the LDS church each year, regardless of their classification. Second, it’s pretty apparent that the green line (children of record) in the upper left is unrelated to the other lines. It’s on a whole different trajectory, and to make things worse, it just stops until 1997 when the “children of record” term comes back but seems to more closely correspond to the “8-year-olds baptized” line. It seems far more plausible that the LDS church may have just changed the terminology for 8-year-old baptisms to children of record, and the green line in 1997 is just a continuation of the blue line before it. It’s a little strange, though, because the line gets a lot more erratic and choppier after the change. Maybe that’s just real numbers, and again, we’ll never know for sure.

One other thing we can know is how these rather inconsistent numbers look as a growth rate. This is the percentage of total membership that’s either an 8-year-old baptism or a change in children of record. Here’s the graph.

Things are clear as mud here too, but we can draw a lot of the same conclusions as before. First, we’re seeing an overall declining growth rate for these figures, regardless of how they’re classified. We can be quite confident in saying there are an increasing number of children in the LDS church each year, but each year the percentage of the membership that is either an 8-year-old baptism or an increase in children of record is smaller.

**Statistical Anomales**

Now I want to point out some interesting statistical anomalies found in the data. The second graph, *Year-Over-Year Change in Membership*, shows the yearly difference in the total number of LDS church members. I got this number by simply subtracting the previous year’s membership total from each year’s membership total since 1970. (For 1970 I subtracted 1969’s total, which is available from the LDS Church.) Each year the number is positive, meaning that each year there are more Mormons than the year before, at least since 1970, and we know how many more there are. We also have conversion and children of record statistics, so we can readily compare conversion details to membership numbers as a whole.

The next bar graph shows how the conversion numbers break down. Let me try to explain this. From the second graph in this entry (*Year-Over-Year Change in Membership*) we know how many more LDS church members there are that year versus the year before, and for each year shown here we’ll call that 100% since it’s the total growth. To break down this yearly 100%, we’ll take the percentage of the growth that’s due to convert baptisms, 8-year-olds baptized, and the total of the two. Together each year, the two statistics should add up to about 100%, allowing some wiggle room for members who have died or left. However, these totals shouldn’t be too far from 100% because, well, you can’t convert more than 100% of the members added and you can’t add members that you don’t baptize.

The green bars show the percentage of the total from convert baptisms, the blue bars show the percentage of the total from increase of children of record or 8-year-olds baptized and the orange bars show the total of the two compared to the reported change in membership. Please note that before 1997 I counted 8-year-old baptisms for the blue bars and after 1997 I counted children of record because I didn’t have much choice. Here’s the graph. You’ll probably have to click on the image to increase the size to make it legible.

This graph uncovers some very interesting anomalies in the data. For instance in 1973 the Mormon church membership was reported to have increased to 3,306,658 from 3,218,908 the previous year, a difference of 87,750 members. But the church also reported that they had baptized 80,128 new converts and 52,789 8-year-olds (totaling 132,917) or over 150% of the membership increase that year. That leaves 45,167 members unaccounted for. When looking again at the graph *Year-Over-Year Change in Membership* we see that 1973 is the lowest year for increase in membership, the only year lower than 100,000. We see this same phenomenon quite a few times in the graph. In 2011 there were 91,350 members unaccounted for. Again, perhaps these members died or left, but there’s a notable discrepancy between baptisms and increase in total church membership.

Even stranger are years like 1989, when the total number of baptisms falls short of the Mormon church membership increase for that year. The LDS church shows a membership increase of 587,234 in 1989, but there were only 318,940 convert baptisms and 75,000 8-year-old baptisms, meaning that 193,294 members were added to the membership total that weren’t baptized. We see the same thing in 1990, in 1999 and in several years in the 1970s and 80s. The phenomenon hasn’t occurred in the past ten years.

It’s anyone’s guess as to what’s going on. Perhaps the LDS church has had a difficult time keeping such vast records straight and the numbers show errors in their collected data, or perhaps the church has made some calculation mistakes in their yearly General Conference reports over the years. We know with certainty that a number of Mormon church members die each year and those decreases could be reflected here. We don’t know whether the LDS church removes resigned members or excommunicated members from their tally, but if they do, that could explain some of the discrepancies.

The LDS church is growing. The church adds a significant number of converts and baptized children to its membership total each year. From the first graph in this post you can see a strikingly linear growth chart showing that LDS church growth is robust and will likely continue indefinitely. Even so, there is a notable decrease in the overall LDS church growth rate, both among converts baptized and among children baptized.

In a follow up post I’ll have a little fun with these numbers and do a little prognosticating on my own. I’ll try to create a reasonable projection for future Mormon church growth and future membership totals based on the trends we’ve seen here. I’ll also compare my numbers to the famous (and laughable) projections created by Rodney Stark of the University of Washington and Baylor University. Stay tuned.