Custodes Futurifor the advancement of humanity

Social factor, barrier 5 of 6

Lack of mentors and networks

A lack of mentors and networks cuts people off from information and introductions.

Evidence

  • Mentoring gap. About 1 in 3 young people, an estimated 16 million, never had an adult mentor, including about 9 million considered at risk (MENTOR, 2014, nationally representative U.S. survey).
  • Enrollment. Among at-risk young people, 45% of those with a mentor enrolled in postsecondary education against 29% of those without. This is a correlation from a survey, not proof that mentoring caused the difference.
  • Source. The data come from an organization that promotes mentoring, so they are rated C.

Proposed and experimental methods

Methods that are proposed, under trial, approved in some places, or tried and then failed. Each shows a stage label and an evidence rating. A stage label shows how far a method has progressed, not whether it works. The stage labels are explained on the social factor page.

  • Algorithmic weak-tie introductions (Large trial, B). LinkedIn experiments randomly varied the connections suggested by its "People You May Know" algorithm for over 20 million people over 5 years, during which 2 billion new ties and 600,000 new jobs were created. Moderately weak ties produced the most job mobility, with diminishing returns beyond that point, and strong ties helped more in less digital industries (Rajkumar et al., 2022). Two of the five authors worked at LinkedIn.
  • Local peer mentors for small business owners (Early trial, B). In a randomized trial with inexperienced women running microenterprises in Kenya, mentoring by an experienced entrepreneur from the same community raised profits by about 20% on average, but gains faded as the mentoring relationships ended, while a formal business class did not raise profits (Brooks et al., 2018).
  • Building cross-class friendships (Theoretical, C). Using 21 billion Facebook friendships, the share of high-income friends among low-income people (economic connectedness) was among the strongest predictors of upward income mobility found to date, and the authors estimate that children from low-income families would earn 20% more on average if they grew up in counties with the connectedness of the average high-income child (Chetty et al., 2022a). About half of the class gap in friendships reflects less exposure in schools and groups, and half reflects "friending bias" even with exposure, and more high-income classmates led to more cross-class friendships only in schools with low friending bias (Chetty et al., 2022b). The 20% figure comes from associations, not from a tested intervention.
  • Not shown to help: school-based mentoring for lasting gains (In wide use, B). A randomized study of Big Brothers Big Sisters school-based mentoring with 1,139 students aged 9 to 16 in 10 cities found that after one school year mentored youth did better academically and more often reported a "special adult," but showed no improvement in classroom effort, self-worth, relationships, or problem behavior, and academic gains were not sustained into the second year (Herrera et al., 2011).
  • Failed: Cambridge-Somerville Youth Study (Failed or reversed, B). In this early randomized trial, 650 at-risk boys aged 5 to 13 were matched in pairs and one of each pair received counseling, activities, and home visits for an average of 5.5 years between 1939 and 1945 (Welsh et al., 2019). Follow-ups in middle age found harmful (iatrogenic) effects in the treated group, with support for contact with deviant peers as a cause (Welsh, 2025). By old age no significant difference in time to death remained (hazard ratio 1.18, 95% CI 0.98 to 1.41) (Welsh et al., 2019).

Sources cited on this page

  1. MENTOR: The Mentoring Effect, executive summary (2014) C Limited: advocacy organization data
  2. Brooks, W., Donovan, K., & Johnson, T. R. (2018). Mentors or teachers? Microenterprise training in Kenya. American Economic Journal: Applied Economics, 10(4), 196-221. link B Moderate
  3. Chetty, R., Jackson, M. O., Kuchler, T., Stroebel, J., Hendren, N., Fluegge, R. B., et al. (2022a). Social capital I: Measurement and associations with economic mobility. Nature, 608(7921), 108-121. link C Limited: (B for the association)
  4. 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. link B Moderate
  5. Rajkumar, K., Saint-Jacques, G., Bojinov, I., Brynjolfsson, E., & Aral, S. (2022). A causal test of the strength of weak ties. Science, 377(6612), 1304-1310. link B Moderate
  6. Welsh, B. C. (2025). The longitudinal-experimental design and the development and prevention of criminal offending over the life-course: Advances in science and policy from the Cambridge-Somerville Youth Study. Criminal Behaviour and Mental Health, 35(2), 89-94. link B Moderate
  7. Welsh, B. C., Zane, S. N., Zimmerman, G. M., & Yohros, A. (2019). Association of a crime prevention program for boys with mortality 72 years after the intervention: Follow-up of a randomized clinical trial. JAMA Network Open, 2(3), e190782. link B Moderate

Every source for this factor is listed on the social factor page.