I made a mistake. The week before conference the LDS Church Growth blog, analyzing a Church news release, projected that the number of missionaries serving could pass 100,000 by the end of 2013 or early 2014. When the news appeared in a facbook group I follow, I thought it seemed overly optimistic. I realized soon after the announcement last October that we would have a surge in missionaries, as 18-year-olds joined the 19 and 20-year-old Elders serving, and as 19 and 20-year-old Sisters joined the 21 and 22-year-old Sisters serving. So, I though, the number of missionaries will jump to 80,000 or 90,000 and then fall back down to something a bit above current levels, as we get to a missionary force that mainly started at 18 (for Elders) and 19 (for Sisters). To confirm this, I put together a spreadsheet model. And I was quite surprised.

The problem I had with the 100,000 number from LDS Church Growth is that it seemed to be simply a projection based on the current number of applications coming in. The LDS Church Growth blog said:

The Church may call as many as 70,000 missionaries in 2013 if it continues to perpetuate the average of 1,400 missionary applications per week for the entire year. This may result in the Church surpassing 100,000 missionaries serving by late 2013 or early 2014…

This left out a lot. Can you really just add the number of missionaries called to those currently serving and guess that will come out right? Some missionaries leave, right? Even if you estimate that half of those serving will return from the mission field during the year, leaving half serving, how do you know that the 1,400 applications a week will keep up for the whole year and give you the 70,000 missionaries calculated? This, among other things, made me doubt that the number of missionaries would reach 100,000.

So I took a different approach. Instead of looking at how many applications were coming in, I though it might be better to look at what proportion of members of a particular age served, and total up how many will be in the mission field based on what age groups will be serving at six month intervals over the next few years. So, if I can find a good estimate of the number of active young men and women at each age, and if I can calculate what proportion will serve a mission, I can total up the number that will be in the mission field at any point in time.

For example, at the end of this year we should have in the mission field the following:

young men who turned 18 during this year

young men who turned 19 during this year (who were also called in 2013)

young men who turned 20 during this year (who were called in 2012 at 19)

young women who turned 19 during this year

young women who turned 20 during this year (who were also called in 2013)

young women who turned 21 during this year (who were also called in 2013)

about half of young women who turned 22 during this year (called in 2012)

senior missionaries

If you know how many are in each of these groups, you can simply add them up and get the number of missionaries serving at the end of this year. For other points in time, you simply adjust the groups you add up based on whether or not they will be serving.

The problem is, of course, that the Church doesn’t report how many young men and young women are in the Church who were born a particular year, nor how many are active and how many serve missions. Except that it does report something that is perhaps just as good, at least for making rough estimates. The Church reports the number of seminary students. And the annual report the Church released this year says that there were about 390,000 seminary students in the 2011-2012 school year, up from 375,000 the previous year. The report gives the number of seminary students each year back to the beginning of seminary, allowing someone like me to estimate the number of students each year and the number of young men and young women each year.

The numbers work out to between 45,000 and 50,000 young men and the same number of young women in seminary. Comparing these to missionary service, it appears that about 45% to 50% of young men in seminary serve missions, while (up to now) 12% to15% of young women in seminary serve missions.

Of course the hope is that these percentages will change with this age change. Will more young men serve because of the age change? We don’t know — I think it is too early to say, and the fact that I’m working with estimates makes me think that I will not be able to tell from my data (the Church will be able to tell at some point in the future, because they don’t have to use estimates).

But, from the data the Church has reported in its news releases, it is very clear that the proportion of young women serving has risen dramatically. Following the announcement last October, the Church reported that as many as half of the applications it received were from women, and the numbers since January, IIRC still show 1/3rd to 40% of applications from women. Even with the fact that the number of potential sister missionaries has tripled, it isn’t possible to see so many applications without an increase in the proportion of young women serving. If my analysis is correct, the proportion of eligible young women serving will increase this year from perhaps 15% last year to almost 30% this year. So, the number of young women serving will more than triple.

So where does this leave us? I’ve put all this together, and produced the following spreadsheet, available for anyone to see on Google Docs. I haven’t made it pretty, so you may have to decipher how I came up with some details. It projects the following:

More than 80,000 serving by the end of June

More than 100,000 serving by the end of December

Nearly 110,000 serving by June 2014

Back down to a little over 100,00 by December 2014

A stable number of 75,000 to 80,000 starting by the end of 2015 — meaning that the bubble from more than one age group starting at the same time (as we are seeing this year with both 18 and 19-year-old Elders starting their missions this year) will have completed their missions.

Like any estimate, these numbers won’t be exactly right, and could be wrong to a large degree. For example, I’ve assumed that about 50% of young men in seminary will serve missions. It is possible that this will only be 45% or less. Or, it could be that the proportion could rise to 55% or more. Likewise, I’m assuming that 30% of young women in seminary will serve missions, rising to 35% when those who turned 16 last year enter the mission field in 2015 (i.e., young women will get used to the idea and will increase participation over time). While it seems certain that the proportion of young women serving will increase, I don’t think anyone knows how high it will go. Personally, I don’t think it will reach the same proportion as young men for decades perhaps, if ever. The 30% to 35% is just my best guess. It remains a guess.

I also assume that the number of senior missionaries will continue to increase at the same rate that it has. I have no idea if that is a good assumption or not. It could be that the increase in young missionaries might turn off some seniors and the number could go down. Or the whole environment could be inspiring, and the number of senior missionaries could increase even faster. Your guess is probably as good as mine.

As always, I’m interested in how others see these numbers. Perhaps other spreadsheet jockeys would like to take a stab at this, or someone can point out an error in my logic. I’ll be surprised if the numbers change by more than 20%, or shift by more than 6 months. But I do recognize that someone else out there might be able to come up with a better estimate than I.

In short, all this took me by surprise. I knew there would be a large, temporary increase in the number of missionaries serving, and that it would settle down later to a significant increase (because of the larger proportion of young women serving). But I had no idea that it would be this big.

What do you think?