The Middle Years Development Inventory (MDI) is questionnaire completed by youth in Grade 4 and Grade 7. Developed by the Human Early Learning Partnership (HELP), an interdisciplinary unit at the University of British Columbia in British Columbia, Canada, the MDI assesses the five areas of youth development (physical health and well-being, connectedness, social and emotional development, school experiences, use of after-school time) that are associated with well-being, health and academic achievement. The MDI is unique as it is self-report questionnaire. It is completed by the children themselves and provides valuable insight about how they think and feel about their experiences both inside and outside of school. In addition, it is a population-level research tool. This means that, rather than evaluating individual children, the MDI measures variations in children’s well-being across time and across provincial, regional and neighborhood settings, providing schools as well as communities in Canada and internationally with information about the development and well-being of their children. The MDI is available for a fee and feedback is provided for both schools and communities.

The MDI website provides overviews of research related to the measure; detailed information of the MDI measure and its administration; maps, data, and reports from multiple waves of data collection; and a library of fact sheets and related publications. The information and data gathered from the MDI is intended to help educators and school administrators identify strengths and weaknesses in the communities they serve and to allow them to better advocate for policy and funding changes.

The Human Early Learning Project is also responsible for the Early Development Instrument (EDI) in British Columbia. The EDI is a population level tool completed by kindergarten teachers from across British Columbia for all children in their classes.