Some time ago I did a small research project on what mission agencies looked for in a good candidate. I asked all of the big agencies to send me a copy of their mission application form and process, and I synthesized these together to get a good view of what they seemed to measure.
I realize what we look for in candidates isn't necessarily a good thing. Still, I think that by looking at all the existing mission agencies, we get a comprehensive view that can keep the good and drop the less-good (except for anything that might be systemic to Western missions as a whole--but that's a subject for a different post).
Mobilizers would do well to keep these "marks" in mind, and use them as a sort of "filter" when looking for candidates. Churches that are mission-passionate might also keep these in mind and look for leadership-development processes that will help Christians mature in each of these areas. (These are not necessarily in order of importance.)
(The factors below go beyond the basic "must have a vision for the unreached".)
1. Basic demographics. Every agency is going to vary a little bit with regard to basic parameters like age, marital status, dependents, etc. YWAM takes younger people; many agencies take only older people (usually determined by educational requirements like college). By putting a basic requirement like college in the mix, the agency is determining in large part the most common age and marital status. So if you have a short list of agencies that you work with, you need to have these basic demographics in mind.
Special note: many agencies have big red flags about people who have been divorced, widowed, or recently remarried. The general rule of thumb: if a person is going through a significant life change, they probably aren't a good candidate right now.
2. Citizenship. Some agencies obviously have citizenship requirements (for example, Beyond only sends US and Canadian citizens; other agencies, like WEC or Wycliffe, etc., are multinationals and can send from other places).
3. Language. You need someone who is proficient in the common language of the agency (for Beyond, English). But being multilingual is a plus. If you already know the language of the place you want to serve, you can shave a couple of years off the inculturation process.
4. Testimony. Does the candidate present clear evidence of their faith in the life they live out? More to the point, can they clearly present their personal testimony? And even more to the point--are they willing to do so? Are they making converts or disciples now, in the church? If they aren't willing to do these things in their home culture, they won't do it in a foreign place.
5. Membership. Most agencies are going to have requirements about a person being a member in good standing of their home church. Sometimes this is a time requirement (e.g. for a few years). Sometimes it's an endorsement requirement. If the church isn't willing to validate their missionary calling, that's a big red flag. (Some churches, obviously, aren't interested in missions or mission-sending, and that's a different issue, which may honestly only be resolved by changing congregations. Again, subject for a different post.)
6. Education, Skills, and Experience. Some agencies make a big deal out of education and training; others, less so. At Beyond, we don't have a seminary requirement, but we do look at education, skills and experience as potential platforms as well as evidence of a lifelong learner. The mark a mobilizer should look for is a person who is fairly well rounded and continuing to add to their store of knowledge and wisdom.
7. Strong. God can use both the strong and the weak, so this isn't about being buff. But a candidate should be able to pass a basic medical examination. I've seen testimonies of people who went to the field in their dying days and had great impact. The general "rule of thumb," however, is that if you're going, you ought to be able to endure (health-wise) for many years.
8. Sane. I name this category a little tongue-in-cheek, but many agencies (ours, definitely) have psychological profiles as part of the candidate assessment process. A person who is not emotionally stable will not be able to get along with others and handle the massive stress of change, culture shock, and adaptation to the new place. One of the most common factors sending people home from the field is team conflict and marital stress, so we try not to send people who are unstable in these areas to start with.
9. Funds. For some agencies, the ability to access or raise the necessary funds is critical. There are several reasons why this is important, and not all of them are "spoken." The reality is, someone who won't raise funds isn't committed to the vision. Someone who can't raise funds may not have the necessary skills (yet) for networking, team building, prayer-partner development, etc. Building for a movement among a people group means being able to develop the funds for tools like Bibles, media, disaster relief, etc.; if a person can't raise funds for personal support, they probably can't raise larger funds for these projects. (This is not unlike a business startup--a person can be a phenomenal worker, but if they can't raise the venture capital they can't start something new.)
10. Doctrine. Every agency is going to have a basic doctrinal standard the person must agree to. Sometimes it's written, and sometimes important parts are unspoken. Know the doctrinal realities of the agencies you work with and be sure to clarify those with potential candidates. Things like the role of women in ministry, opinions on charismatics, etc., are often unwritten but very important to know.
11. Flexibility. Last but definitely not least, the person you're looking for is more flexible and less rigid. They have to be able to be strong in important areas (for example, theology and witness and boldness for Christ) and flexible in others (schedules, plans, etc). They must be able to set goals, yet not fall apart when the goals aren't met.
Here are a few additional points I would make, beyond the study:
a) are they interested - do they evidence any interest in other cultures?
b) are they willing - do they say things like "I'm glad I'm not called" or "I wish I could do that"?
c) are they available - do they have significant family or monetary ties that are difficult to break?
d) do they show up for mission-related events?
This may seem like a long list. A lot of it is just plain common sense. Some of the filters are easily seen (demographics, citizenship, language); others are easily obtained (if you ask them, will they easily share their testimony?). Others only come out over time. It's important to keep your eyes open and know when the list is "bendable" and when something is a "red flag." Pour your time into the most probable folks, while being available for "wildcards" and the "less likely." And remember, mobilization is a long marathon, not a short sprint--someone who says "no" now, or who by these measures is a bad candidate now, may be an ideal one later on. Don't give up.