Here’s the data: Over the years, the number of missionaries sent has varied, but the number of missionaries sent per million affiliated Christians – that is, the number of missionaries sent out by every million church members – has been pretty consistent. The Atlas for Global Christianity (from the Center for the Study of Global Christianity) reports in 1910 we sent 101 missionaries per million Christians; in 2010, we sent 184 per million. We doubled our sending capacity, but we’re still on the order of 100 or so.

To me, that’s not hugely different, and could be accounted for in any number of ways – easier to send now, more countries are sending workers now, more agencies send more women now, etc. On the other hand, the workers that we sent are generally being received as 35 (1910) to 58 (2010) per million people. This equals roughly 5 to 6 missionaries per 100,000 people today, or about 1 per 20,000.

Is 58 per million, or 1 per 20,000, ‘enough workers’? To answer, we must ask: “There are not enough workers in the harvest–to do what?”

If we expect an individual worker to ‘harvest’ 20,000 people–to see 20,000 people at minimum evangelized, better brought into the Kingdom, even best discipled–I think we are expecting a lot, too much of the typical worker. I can’t think of a single worker, ever, in history, who has personally discipled 20,000 people, and the worker who has personally–by himself, as a result of his individual labor–baptized 20,000 is maybe only slightly less rare.

When we say ‘there are not enough workers in the harvest,’ we commonly mean one of two things:

• that this particular harvest field is completely unengaged (in which case, the statement its true); or,
• that we don’t have enough foreign workers to interact with everyone in the field.

But what if foreign workers shouldn’t be interacting with everyone in the field? What if we asked, “Are there enough workers in the harvest to raise up local workers to see it harvested?” What if the missionary has a strategy of raising up local works (churches, evangelists, disciple makers, etc), and they see these 20,000 discipled? Better: what if a 5-person team (a five-man band, as in the common story trope, perhaps?) were to work a similar strategy, targeting 100,000?

Ironically, what I’ve described–the worker raising up local believers, seeing churches planted, etc.–has historically often been a key element of a missionary strategy, even if we don’t think of it when we think of this question.

If you want to see how it was done in Hunan province in the 1920s, I ran across this excellent case study on Frank Keller from IBMR. Local workers made the success possible, and Frank abandoned his own good evangelistic work to focus on raising up more of them. Five who raise up five local teams (not recruiting more workers) immediately get the Gospel into the local culture. If those five likewise raise up 5 teams, you’ve planted not just workers but a reproducible process, and cut the task to about 4,000 per team at the third generation.

Now the task of evangelizing, converting and discipling 100,000 souls is more doable (and you’ve planted the church to boot). Yes, it means the missionary team is only responsible for about 25 souls, not 100,000, and this perhaps is more difficult to discuss in a missionary letter back home. But not impossible.

Is our existing level of missionary sending, therefore, enough? To do what we traditionally expect missionaries to do (be little stereotypical Billy Grahams), no. But with the right strategy–yes, we are sending at the right levels. (Not necessarily to the right places, but that’s a different issue.)

We then have two choices: one, send more teams with the right strategy (thus solving both the strategy and the placement issue), or two, if we believe this to be the case, persuading existing teams to a better strategy than the one they are using.