The work performed by short-term missionaries can never replace long-term efforts made by career missionaries, and it is not difficult to understand why. For a missionary to learn the people's language, to identify with them, and to nurture a young church to maturity take time, and these can never be achieved through short-term ministries (Hiebert 1985:282).
Although many have criticized short-term missions for its unreliable results and differing motivations of the people going on such short-term ministries, it is clear that short-term missions can be effective in helping people and churches catch the vision of what God is doing around the world. According to Steve Pettis who has led teams on short-term missions trips, a key benefit of such trips is what it does for those who participate. He said that a vast majority of those who went, have their eyes and hearts opened to what God is doing throughout His Kingdom, and have brought back their experiences to the home church to pray as a body for the universal church with greater knowledge. They have also committed themselves to giving to the growth of the Kingdom, and some have sensed or confirmed God's call for them to full-time missions (Pettis 2007).
Short-term missions play an important role in helping participants of missions ministries to pray more diligently and fervently with understanding of the ministry, the challenges field missionaries face everyday, and the needs of the people being ministered to. Short-term missions are also effective in providing potential missionaries insights of what is involved, and hopefully arouse them in the desire to serve the LORD in longer term mission ministries in their trip, and prepare them for dedicated long-term mission work.
Hiebert, G. Paul (1985) "Chapter 10: The Missionary Role", Anthropological Insights for Missionaries. Michigan: Baker Book House, pp. 255-283.
Pettis, Steve (2007) "The Place of Short-Term Missions in Today's World", Indiana Wesleyan University, http://cas.indwes.edu/botany_glen/pettis.htm (Accessed 28 April 2007).