The standards of STM excellence that our committee compiled a few years ago is a good place for anyone interested in the subject to start.
Here is Standard
#7: THOROUGH FOLLOW-UP.

An excellent short-term mission assures debriefing and appropriate follow-up for all participants, and is expressed by:

7.1 Comprehensive debriefing (pre-field, on-field, post-field)

7.2 On-field re-entry preparation

7.3 Post-field follow-up and evaluation

We recognize that thorough debriefing and follow-up is a crucial aspect of STM. As in the parable of the talents (Matt. 25:14-30), we seek to help all participants invest and multiply the STM experience God has entrusted to them. Therefore in all our STMs, we strive to provide relevant debriefing in each stage (pre-field, on-field, post-field), including on-field re-entry preparation for goer-guests and post-field follow-up for all participants as appropriate. We acknowledge that thorough follow-up will help participants process the STM, apply lessons learned, and promote continued personal growth (spiritual, emotional, intellectual, cross-cultural, relational, and other growth). We also acknowledge that thorough follow-up can help participants integrate the entire STM into life for kingdom purposes, solidify transforming life change, and provide opportunity for continued personal commitment to Christ and the people of his world. We further acknowledge the importance of assessing our mutual efforts with one another and therefore pledge to implement timely evaluation of the outreach to help identify unresolved issues (if any), to amend such issues, and to enhance our partnership’s future STM efforts.

7.1 Comprehensive debriefing (pre-field, on-field, post-field)

We pledge to provide appropriate and thorough debriefing throughout every stage of the mutually designed program to help all participants process the pre-field training, on-field implementation, and post-field challenges. We further pledge that our debriefing will be designed to enable participants to better apply lessons learned, to nurture their continued growth, and to bear spiritual fruit.

7.2 On-field re-entry preparation

We pledge to provide re-entry preparation for goer-guests prior to leaving the field to facilitate balanced re-entry into the home culture, preparing them for adjustments and challenges they may face.

7.3 Post-field follow-up and evaluation

We pledge to provide post-field follow-up for all participants to help cement life change and cultivate ongoing growth and commitment to Christ and his world. We pledge to candidly evaluate our mutual efforts with one another as a means to enhance future programs. We further pledge that the results of evaluations will be communicated to relevant leaders, for the improvement of future STMs and the keeping of pertinent permanent records. We also pledge confidentiality, integrity, and accuracy in the evaluation and record keeping process.