Middle Years Development Instrument


What is the Middle Years Development Instrument (MDI)?

The Middle Years Development Instrument (MDI) is a self-report questionnaire completed by children in Grades 4 through 8. It asks them how they think and feel about their experiences both inside and outside of school. Both the Grade 4/5 questionnaire and the Grade 6/7/8 questionnaire include questions related to the five areas of development that are strongly linked to well-being, health and academic achievement.

Physical Health & Well-Being

Children evaluate their own physical well-being in the areas of overall health including emotional well-being, physical activity, nutrition and sleeping habits.


Children are asked about their experiences of support and connection with the adults in their schools and neighbourhoods, with their parents or guardians at home, and with their peers.

Social and Emotional Development

Children respond to questions about their current social and emotional functioning in 7 areas: optimism, self-esteem, happiness, empathy, prosocial behaviour, sadness and worries.

School Experiences

Children are asked about their school experiences in 4 areas: academic self-concept, school climate, school belonging, and experiences with peer victimization (bullying).

Use of After-School Time

Children are asked about the time they spend engaged in organized activities such as sports, music and art, as well as the time they spend watching TV, doing homework and playing video games.


Introduction to the MDI - Video


Why look at populations, NOT individuals?

The MDI is a population-level research tool. This means it measures developmental change or trends in populations or groups of children. Although individual students complete the questionnaire, the results are not used to evaluate individual children, nor are they used to rank teachers, neighbourhoods, schools or school districts. Understanding how populations of children are doing allows educators, parents, researchers, community organizations and policy makers to make informed decisions about investments in new or adapted programs and in broad policies that support children and families.

The MDI collects information that can be reported and mapped at a neighbourhood level and then made public. It provides an opportunity to see variations in children's well-being across time and geographies. Educators, parents, researchers, community organizations and policy makers can view their own MDI data in the context of other neighbourhoods and school districts in British Columbia, providing a better sense of strengths and weaknesses.

Why children's voices?

Article 12 of the United Nations Convention on the Rights of the Child states that children have a right to give their opinion and be listened to by the adults around them. The MDI is a unique tool that allows us to hear children’s voices. It gives us insight into areas that have great significance in children’s lives but are not typically evaluated by other forms of assessments.

Rather than evaluating academic progress, the MDI gives children an opportunity to communicate to adults in schools and communities about what their experiences are inside and outside of school. In this regard, the MDI has great potential to provide educators, parents, researchers, community organizations and policy makers with much needed information about the psychological and social worlds of children during middle childhood. By reviewing and sharing MDI results we are validating the opinions and concerns of children and are better prepared to move toward actions that will create supportive environments where children can thrive.

How are MDI data used?

MDI results are summarized into maps and reports that communities, schools, and governments can use to inform their work. Learning how children are currently faring across neighbourhoods and school districts means that supports and services can be tailored to families and children where and when they are needed. 

Discover MDI – the Field Guide for the Middle Years Development instrument (MDI) – is a powerful tool to understand and support children’s well-being and positive development in the middle years. Discover MDI guides you on your journey with the MDI—from understanding the MDI and the importance of middle childhood, to collecting, exploring, and sharing MDI data, to using MDI data to catalyze action designed to improve the well-being of children in the middle years. 

MDI data can be used to:

Who uses MDI data?

Schools and communities use the information included in MDI reports to initiate conversations about how the needs of children in their middle years can be better addressed.

Researchers use MDI data to dig deeper into important questions about the genetic, biological, and social determinants of children’s health and development. Their research, in turn, helps to inform policy and program development.

Government, policy-makers, and not-for-profit organizations use the maps and data that come from the MDI questionnaire to plan economic investments, policy changes and program development.

How was the MDI developed?

The foundation for the Middle Years Development Instrument was laid in 2006 when a University of British Columbia (UBC) research team led by Dr. Kim Schonert-Reichl, in collaboration with the United Way of the Lower Mainland, completed a study of over 1,400 children in 8 school districts in Metro Vancouver. This study asked children to complete a daily diary of their activities, and to answer a questionnaire about their well-being. The results of this study have been recorded in a report called Middle Childhood Inside and Out: The Psychological and Social Worlds of Canadian Children Ages 9-12. The report is available as both a Full Report and Summary

The MDI was created, in part, from this early pilot questionnaire used in 2006. Following that study, a small Technical Committee of principal investigators from UBC, graduate students, and staff from both the Vancouver School Board and United Way set to work on a revised survey that could be used at a population level. Question items for consideration were taken from surveys previously tested and validated in research with children. Questions with a high degree of reliability were selected within five broad categories: Social and Emotional Development; Connectedness; School Experiences; Physical Health and Well-Being; and Constructive Use of Time. Each potential survey question was subjected to scrutiny based on factor analysis and its relevance to the major categories established by the Technical Committee. Considerable input was also provided by children, parents, teachers and community groups working with children in their middle years. Prior to district-wide implementation, the MDI underwent three pilot studies in Vancouver to test its reliability and validity. Following each pilot study, the tool was strengthened and streamlined into its current form.

The MDI tool is licensed. For more information about our licensing, please contact MDI@help.ubc.ca.