I have been asked many times about the effectiveness of the method widely used by Jehovah's Witnesses; going door to door "cold turkey" or attempting to visit people in their homes without any invitation or prior relationship having been established. The organization is not very public about its membership data, so it has been difficult to give a direct answer. I was glad to find out today that a French scholar has gained access to the data and has published some clear evidence on this question.
The worldwide growth rate for Jehovah's Witnesses last year (2008) was 2.1 percent, a decent growth rate although significantly short of the seven percent among the Assemblies of God, or the five percent among Evangelical Christians in sub-Saharan Africa or the 3.6 percent of the worldwide Seventh-day Adventist Church. More to the point is data on how many hours of evangelistic activity (going door to door or standing with literature on city street corners or in subway stations) must be invested per new convert.
It requires twice as many hours per convert in the U.S. and Europe as it does in Africa, Latin America and Eastern Europe. Even more to the point is the change in these data over recent decades. In 1980 in the U.S. it took 2,915 hours of evangelistic labor per convert, and by 2008 that had more than doubled to 6,120 hours per convert. In Canada it went from 3,342 hours to 9,082 hours per convert over the same period. In the United Kingdom it went from 3,511 hours to 7,074 hours per convert. In Italy it went from 2,540 hours to 10,121 hours per convert.
Clearly the "population seems to be more resistant to Witnesses' proselytism than used to be the case," comments Religion Watch in reporting this research. But even at the lowest rate (2,540 hours per convert in Italy in 1980) this seems a very inefficient approach. A key theological consideration: Is it good stewardship of the time and talent that God has placed in the church to use such an inefficient method? Jehovah's Witnesses believe it is an exercise necessary to salvation, so they may not be very concerned about the efficiency or effectiveness of the method. Most Christians do not believe that you can work your way into salvation in this way, so the stewardship issues become more pronounced when considering this or any methodology.
An argument could be made that perhaps this method should be used in the southern hemisphere, where it has a more effective rate. In churches with large numbers of people and small resources of other kinds, a labor intensive approach to evangelism makes more sense that in the context of the U.S. and Europe. But remember that the current data in these fast-growing areas is near the 3,000 hours per convert mark. How long will that continue to be good stewardship? Italy was at this level in 1980 and now it has one of the highest rates in the world. Does this method actually create resistance and eventually burn out its effectiveness?
My thanks to the staff at Religion Watch for picking up this research by Bernard Blandre in a French-language journal, Mouvements Religieux. I do not read French well enough to have found this unaided.