Does short term missions produce long term missionaries?

I have been involved in hosting short-term teams for over twelve years. I got called to missions on a short-term mission trip with YWAM and have heard that 90% of long-term missionaries first got involved in missions because of a short-term trip. So, I have always been a big fan of short-term missions because I have seen the impact that they have had on people's lives and know that they have played a role in seeing people go long-term. Participants on our short term mission trips usually go home with a totally different worldview, gain a greater burden for the lost, see the poor in a new light, and catch a vision to live more missionally.

I have always worked on the assumption that the more people we have going on short-term mission trips, the more long-term laborers we would see going into the harvest field. However, the latest numbers in Mission Maker magazine say that the number of short-term missionaries increased from 140,000 in 1984 to over 1.6 million in 2005. MissionNext says that the number of long-term American missionaries sent out has dwindled from 55,000 in 1988 to 35,000 in 2006. So, while the short-term mission movement has multiplied almost ten times in the past twenty years, the long-term mission force has roughly been cut in half.

So, where is the long-term fruit from the short-term mission efforts. Some people say that it is coming and that it just takes awhile (average seven years) for missionaries to hit the field after getting the call. Some say that it will never happen due to the amount of debt and lack of finances to send Americans. Some say that less people are willing to go long-term now that they can see that they can get their "missions fix" on a short-term trip. What do you think?