Big Brothers Big Sisters is an early intervention and prevention mentoring programme matching volunteer mentors with young people between 6 and 12 years old who are facing adversity and want and need a positive role model in their life. They can stay with their mentor until 18 years. As the world's largest mentoring programme, Big Brothers Big Sisters has been operating for over 100 years. In the 25 years the programme has been in Aotearoa, we have supported over 4000 matches. There are still hundreds of young people waiting for a mentor across the motu, so we would love your help. $150,000 per year. The cost to keep one person in prison... or to ignite potential in 80 young people by giving them a mentor? Boston Consulting Group found that every $1 invested in Big Brothers Big Sisters mentoring generates $23 in social return on investment.