Short term missions group
The face of missions involvement is a different landscape than it was 40 years ago. 
 
Gone are the days of national geographic style slide presentations from far-away lands that captivated our imaginations. (As a third grade child, I begged my work-weary mother to go to a slide show depicting rafting down the Colorado River given by Barry Goldwater - Arizona senator and ex-Presidential candidate- at our school one evening. She gave in and we went.) The invention of the Internet, the ease and affordability of international travel has enabled a new generation to desire personal involvement. No longer will the career missionary be the sole point of the spear to impact lives. 
The challenge is to wrestle with the concept of what spreading the gospel means, being good stewards of resources, introducing missions to a generation that processes thought differently than their grandparents and parents, keeping the execution and fulfilling the great commission as the core of our our corporate church effort.
 
Missions involvement has taken on a new face - pastor, missions committee member, missionary - learn to adapt or go the way of the Dodo bird into extinction.
 
Consider a couple thoughts while you wrestle. 

Take this example. A group of eighteen students raised $25,000 to fly to Honduras for spring break. They painted an orphanage, cleaned the playground, and played with the children. Everyone had a great time, and the children loved the extra attention. One student commented: "My trip to Honduras was such a blessing! It was amazing the way the staff cared for those children. I really grew as a Christian there."

The Honduran orphanage's yearly budget is $45,000. That covers the staff's salaries, building maintenance, and food and clothes for the children. One staff member there confided, "The amount that group raised for their week here is more than half our working budget. We could have done so much with that money.” taken from: The cost of short-term missions, by JoAnn Van Engen

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Estimates are difficult to quantify, but some estimate the participation to be around 2 million short-term participants annually, with around 2 billion dollars being required to fund the efforts.
 
Just how big is short-term missions (STM)? As a grass-roots, decentralized movement, its scope is difficult to determine. And yet your own estimate of between 1 million and 4 million North American short-term missionaries every year may well be a conservative estimate. The sociologist Christian Smith, based on national random survey data, reports that 29 percent of all 13- to 17-year-olds in the U.S. have "gone on a religious missions team or religious service project," with 10 percent having gone on such trips three or more times. That is, his data indicates that far more than 2 million 13- to 17-year-olds go on such trips every year. 
 
 

I am not for the narrative that has typically driven these trips: "We are going because there's this tremendous need out there that we have to meet. And there's this burden that we have as the wealthy country to go and do something in another place." I support transforming this narrative so that it becomes, "How can we connect with what God is doing in other parts of the world? How can we learn to be good partners with Christians already in these places? How can we participate in what the church is already doing in these countries in effective ways?"
Wheaton College anthropologist Brian M. Howell 

 
In light of such sobering thoughts, we need not resist missional tourism at all costs. There are great benefits that impact participants. There is something to be said about seeing firsthand how that God can use you in a foreign culture. People will be taking vacations, why not take that opportunity to leverage it for kingdom impact? Yes it is new, it is a new day.
 
It need not be painful, if a person is willing to implement a few ideas:

Embrace change

The challenge is not to try and recapture bygone days, those chapters have already been written and the ink is dry. We must embrace the new and changing culture, even as it develops.My encouragement is to pray fervently in order to maintain a balance the attention directed towards both short and long-term missions. We must keep church planting at the forefront of what we do, if we do truly believe that Jesus loves the church.

Focus on the task not solely the delivery method

There must be some way to be able to introduce the great commission to a new generation and find ways to involve them personally in fulfilling the task that Jesus left his church.

Remain flexible

Those leaders and institutions that do well in embracing the changing landscape of missions involvement will find a new generation excited about leaving the fingerprints of Jesus on a needy world.