Youth mentoring programmes can improve outcomes across academic, behavioural, emotional and social areas of young people's lives. These impacts are small, but nevertheless significant (DuBois et al, 2011). There is no evidence that youth mentoring programmes can improve physical health, although there are few studies that examine this particular outcome. There are three key themes in the research evidence about what makes an effective youth mentoring scheme.

1. Programme design and delivery

• The recruitment of mentors (Du Bois, 2011), their training (Kanchewa et al, 2014) (Wilson et al, 2017) (Schwartz et al, 2013) (MacArthur et al, 2017), and ongoing motivation (DeWit et al, 2016) are associated with effective programmes.
• The matching process is important (Wilson et al, 2017) (DuBois et al, 2011) (Sanyal & Rigby, 2017)
• Mentoring comes in different forms: group activities, online activities, and one to one activities, all of which can be effective (Eby et al, 2012) (Lindsay et al, 2016) (Wilson et al, 2018)

2. Mentee and mentor characteristics

• Mentee choice and agency is important (Schwartz et al, 2013). Giving agency to young people means longer relationships and better outcomes. Motivation is also important, both for mentees (Bogat et al, 2008) (Chan and Ho, 2008) and mentors (DeWit et al, 2016).
• But shared backgrounds (Eby et al, 2012) (DeWit et al, 2016) and culturally- sensitive matching are also important (Schwartz et al, 2013) (Bogat et al, 2008). Culturally- sensitive matching helps to make sure there are similarities in culture, ethnicity and race between mentors and mentees, or more broadly being aware of, and taking into account, differences. It is important to avoid making assumptions about what shared interests and backgrounds are important to mentees.

3. Relationships

• Longer relationships between mentees and mentors are associated with better outcomes (Schwartz et al, 2013) (MacArthur et al, 2017) (Eby et al, 2012) (DuBois et al, 2011). Early (unplanned) termination of relationships can lead to negative outcomes (Du Bois et al, 2011). Girls are more likely to drop out of mentoring programmes than boys (Du Bois et al, 2011).
• The quality of the relationship important (Du Bois et al, 2011) (MacArthur et al, 2016) (Bogat et al, 2008). Factors that improve the quality of mentoring relationships include the duration and frequency of visits, variety of activity, and providing both emotional and instrumental support (DuBois and Silverthorn, 2005) (Lymburner, 2006) (Schwartz et al, 2013)
• Mentors also benefit from positive relationships (Lindsay et al, 2016)