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Mentoring: Big Brothers Big Sisters School-Based (including volunteer costs)

Public Health & Prevention: School-based
Benefit-cost methods last updated December 2023.  Literature review updated May 2018.
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Big Brothers, Big Sisters (BBBS) aims to promote greater confidence, educational success, and avoidance of risky behaviors through one-on-one mentoring. BBBS can be provided in schools or in other community settings. This analysis represents BBBS programs provided in schools.

In BBBS school-based mentoring, mentors and students meet regularly at school for one-on-one relationship building and guidance. Community-based organizations coordinate with school staff and provide mentors with training and oversight. Participating youth, aged 6-18, come predominantly from low-income, single-parent households. In the study used in this meta-analysis, most volunteers were high school or college students. Volunteers met with their mentees for an average of three 1-hour sessions per month over a period of about five months.
For an overview of WSIPP's Benefit-Cost Model, please see this guide. The estimates shown are present value, life cycle benefits and costs. All dollars are expressed in the base year chosen for this analysis (2022). The chance the benefits exceed the costs are derived from a Monte Carlo risk analysis. The details on this, as well as the economic discount rates and other relevant parameters are described in our Technical Documentation.
Benefit-Cost Summary Statistics Per Participant
Benefits to:
Taxpayers $278 Benefits minus costs ($2,934)
Participants $148 Benefit to cost ratio ($0.18)
Others $245 Chance the program will produce
Indirect ($1,126) benefits greater than the costs 1%
Total benefits ($455)
Net program cost ($2,479)
Benefits minus cost ($2,934)

^WSIPP’s benefit-cost model does not monetize this outcome.

Meta-analysis is a statistical method to combine the results from separate studies on a program, policy, or topic in order to estimate its effect on an outcome. WSIPP systematically evaluates all credible evaluations we can locate on each topic. The outcomes measured are the types of program impacts that were measured in the research literature (for example, crime or educational attainment). Treatment N represents the total number of individuals or units in the treatment group across the included studies.

An effect size (ES) is a standard metric that summarizes the degree to which a program or policy affects a measured outcome. If the effect size is positive, the outcome increases. If the effect size is negative, the outcome decreases. See Estimating Program Effects Using Effect Sizes for additional information.

Adjusted effect sizes are used to calculate the benefits from our benefit cost model. WSIPP may adjust effect sizes based on methodological characteristics of the study. For example, we may adjust effect sizes when a study has a weak research design or when the program developer is involved in the research. The magnitude of these adjustments varies depending on the topic area.

WSIPP may also adjust the second ES measurement. Research shows the magnitude of some effect sizes decrease over time. For those effect sizes, we estimate outcome-based adjustments which we apply between the first time ES is estimated and the second time ES is estimated. We also report the unadjusted effect size to show the effect sizes before any adjustments have been made. More details about these adjustments can be found in our Technical Documentation.

Meta-Analysis of Program Effects
Outcomes measured Treatment age No. of effect sizes Treatment N Adjusted effect sizes(ES) and standard errors(SE) used in the benefit - cost analysis Unadjusted effect size (random effects model)
First time ES is estimated Second time ES is estimated
ES SE Age ES SE Age ES p-value
11 1 439 -0.240 0.067 11 n/a n/a n/a -0.240 0.001
11 1 439 0.260 0.067 11 n/a n/a n/a 0.260 0.001
11 1 480 -0.082 0.086 11 n/a n/a n/a -0.082 0.336
11 1 439 -0.060 0.067 11 -0.033 0.043 14 -0.060 0.370
11 1 439 -0.023 0.067 11 -0.023 0.067 13 -0.023 0.730
1In addition to the outcomes measured in the meta-analysis table, WSIPP measures benefits and costs estimated from other outcomes associated with those reported in the evaluation literature. For example, empirical research demonstrates that high school graduation leads to reduced crime. These associated measures provide a more complete picture of the detailed costs and benefits of the program.

2“Others” includes benefits to people other than taxpayers and participants. Depending on the program, it could include reductions in crime victimization, the economic benefits from a more educated workforce, and the benefits from employer-paid health insurance.

3“Indirect benefits” includes estimates of the net changes in the value of a statistical life and net changes in the deadweight costs of taxation.
Detailed Monetary Benefit Estimates Per Participant
Affected outcome: Resulting benefits:1 Benefits accrue to:
Taxpayers Participants Others2 Indirect3 Total
Externalizing behavior symptoms Criminal justice system $21 $0 $55 $11 $87
Labor market earnings associated with high school graduation $52 $123 $67 $0 $242
K-12 special education $93 $0 $0 $46 $139
Health care associated with externalizing behavior symptoms $123 $35 $127 $61 $345
Costs of higher education ($12) ($10) ($3) ($6) ($31)
Internalizing symptoms K-12 grade repetition $1 $0 $0 $0 $1
Program cost Adjustment for deadweight cost of program $0 $0 $0 ($1,239) ($1,239)
Totals $278 $148 $245 ($1,126) ($455)
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Detailed Annual Cost Estimates Per Participant
Annual cost Year dollars Summary
Program costs $2,101 2016 Present value of net program costs (in 2022 dollars) ($2,479)
Comparison costs $0 2016 Cost range (+ or -) 30%
The estimated cost per participant is based on the average per-youth per-day cost to implement the program in Washington ($5.32) and the average number of program days in the study included in this analysis. We also include the estimated value of one hour of volunteer time ($39.99) and the average number of intervention hours in the study included in this analysis. The average per-youth per-day cost was calculated based on 2016 program cost and number of youth program participants in three Washington BBBS agencies (provided by BBBS of Puget Sound in October 2017). Except for fundraising costs, all expenses are included (e.g., buildings, phones, staff). The value of volunteer time is based on the Washington Office of Financial Management’s estimated average adult salary for 2015, multiplied by 1.44 to account for benefits.
The figures shown are estimates of the costs to implement programs in Washington. The comparison group costs reflect either no treatment or treatment as usual, depending on how effect sizes were calculated in the meta-analysis. The cost range reported above reflects potential variation or uncertainty in the cost estimate; more detail can be found in our Technical Documentation.
Benefits Minus Costs
Benefits by Perspective
Taxpayer Benefits by Source of Value
Benefits Minus Costs Over Time (Cumulative Discounted Dollars)
The graph above illustrates the estimated cumulative net benefits per-participant for the first fifty years beyond the initial investment in the program. We present these cash flows in discounted dollars. If the dollars are negative (bars below $0 line), the cumulative benefits do not outweigh the cost of the program up to that point in time. The program breaks even when the dollars reach $0. At this point, the total benefits to participants, taxpayers, and others, are equal to the cost of the program. If the dollars are above $0, the benefits of the program exceed the initial investment.

Citations Used in the Meta-Analysis

Herrera, C., Grossman, J.B., Kauh, T.J., & McMaken, J. (2011). Mentoring in schools: An impact study of Big Brothers Big Sisters school-based mentoring. Child Development, 82(1), 346-361.