This article presents an instrument for measuring the effectiveness of literacy programmes for youth and adults. To assess the impact of participation on individual learners' lives and their environment, the authors developed a structure comprising five main dimensions: (1) "personal sphere" (six sub-dimensions); (2) "social skills" (six sub-dimensions); (3) "life project" (four sub-dimensions); (4) "knowledge" (five sub-dimensions); and (5) "economic situation" ´(five sub-dimensions). Phase 1 of developing this instrument included the definition of dimensional and sub-dimensional features; Phase 2 comprised drafting the design of the measurement scale. During Phase 1, the authors conducted focus group discussions and individual interviews with 15 students, 14 teachers, 10 graduates and 2 former managers of a Colombian second-chance adult education programme called "Avancemos" [Let's go forward]. The programme was launched in 1993 and has since been further developed by the University of Ibagué. During Phase 2, six specialists in education and psychology validated the survey items in an expert trial. In the third phase of development, the authors finalised a survey questionnaire to test their scale and distributed it among 132 "Avancemos" graduates, of whom 124 (63 women and 61 men) returned completed forms. In their analysis of the results, the authors found that their instrument, which they named EduIMPACT, had proved useful for evaluating and acting upon the programme's perception among its target group.