Big Brothers Big Sisters

Updated: Nov 20, 2017
Evidence Rating:
Suggestive Tier


  • Program:

    A community-based mentoring program for disadvantaged youth ages 6-18.

  • Evaluation Methods:

    A single randomized controlled trial (RCT) with a sample of 1,138 youths, ages 10-16.

  • Key Findings:

    RCT shows sizable decrease in youths’ drug and alcohol use and violent behavior over an 18-month follow-up period.

Big Brothers Big Sisters’ community-based mentoring program matches youths age 6-18, predominantly from low-income, single-parent households, with adult volunteer mentors who are typically young (20-34) and well-educated (the majority are college graduates).

The youth’s parent/guardian applies for his or her child to be matched with a mentor through a written application and child/parent interview. Potential mentors are screened by a Big Brothers Big Sisters caseworker through a personal interview, home visit, and criminal, background, and reference check to ensure that they are not a safety risk and are likely to form a positive relationship with the youth. Prior to a match being made, the youth and parent meet with the potential mentor; the match’s completion requires the parent’s approval.

The mentor and youth typically meet for 2-4 times per month for at least a year, and engage in activities of their choosing (e.g. studying, cooking, playing sports). The typical meeting lasts 3-4 hours.

For the first year, Big Brothers Big Sisters caseworkers maintain monthly contact with the mentor, as well as the youth and his or her parent, to insure a positive mentor-youth match, and to help resolve any problems in the relationship. Mentors are encouraged to form a supportive friendship with the youths, as opposed to modifying the youth’s behavior or character.

In 2008, Big Brothers Big Sisters served 255,000 youths at 470 agencies nationwide. The national average cost of making and supporting a match is approximately $1,512 in 2017 dollars.

Click here for Big Brothers Big Sisters’ website.

To see our full evidence summary:
Download PDF


Grossman, Jean Baldwin and Joseph P. Tierney. Does Mentoring Work? An Impact Study of the Big Brothers Big Sisters Program. Evaluation Review, Vol. 22, No. 3, June 1998, pp 403-426.
Click here for a copy of this study. (Big Brothers Big Sisters website)