I like the way this post discusses When Helping Hurts and short term missions...
Obviously, we don't think that churches or God's people mean to do harm in the countries where they go to serve and share the gospel. We don't think that churches want to use money to fund a trip or experience, instead of using that money in a more positive, useful, long-reaching, Kingdom building way. After living in Haiti, we simply recognize that serving a country like this is complex. People who have lived here for 20 years are still struggling to understand how best to love and care for the people of Haiti. So obviously, planning a healthy, short-term mission trip, from the States, thinking through all the ramifications, and making sure the trip's end result (for the Americans going, and the people in the country they are serving) is beneficial is also going to be complex. Probably more complex.
Lots of ministries in Haiti need money. Orphanages need generators. Children's homes need new roofs. So, sending a team of people to play with orphans, instead of sending money for a generator is a hard call to make. If two team members stayed home and sent the money it would cost them to actually go, an orphanage could have a generator. Complex issues to think through. Sending a team to build a roof on a children's home in a country where local men are in desperate need for work, is again...a hard call to make. How can a short term team pour into Haiti in a sustainable, healthy way?
From All Things Hendrick via Rage Against the Minivan