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aabout early development instrument data

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  • For each data source, information about data collection and analytical methods, limitations, the citation and additional resources can be found on the Data Sources and Methods page.


Original source: Ontario Ministry of Children and Youth Services.
Cite as: Early Development Instrument, 2007, 2010 and 2015, Ontario Ministry of Children and Youth Services. Offord Centre for Child Studies, McMaster University.


Data Collection Methods

  • The Ontario Ministry of Children and Youth Services contracts the Offord Centre for Child Studies at McMaster University to implement the Early Development Instrument (EDI) across the province in three-year cycles.
  • EDI questionnaires were completed by senior kindergarten teachers during the second half of the school year in all publicly funded schools for all the senior kindergarten children in their class.
  • Students that were in the classroom and taught by the teacher for at least one month were included in the assessment.
  • To improve accuracy, teachers received standardized training about how to complete the questionnaire.
  • The EDI questionnaire is available in English and French.
  • The EDI tool contains more than a hundred questions covering five domains and 16 sub-domains. Each of the sub-domains represents a relatively homogenous aspect of a child’s development. The five domains are as follows:
    1. Physical Health and Well-being
    2. Social Competence
    3. Emotional Maturity
    4. Language and Cognitive Development
    5. Communication Skills and General Knowledge.
  • Completed EDI questionnaires were sent to the Offord Centre for Child Studies for data entry and preliminary analysis.

Data Analysis Methods

  • Invalid EDI cases (missing data on more than one EDI domain), cases missing a sex designation, cases with residential postal codes outside of Peel and cases identified as having a special need or missing special needs designation were removed from analysis.
  • Since the EDI is a population-based measure, individual results are aggregated.
  • Each EDI domain is scored from 0 to 10 with scores closer to 10 indicating more advanced levels of school readiness.
  • Cut-points were used to identify children who were ‘Vulnerable’ for each EDI domain. Ontario baseline cut-points were used as the standard for comparison. All Ontario communities that completed the EDI from 2004 to 2006 were included in the calculation of the Ontario baseline cut-points. Vulnerability was defined as being at or below the 10th percentile according to the following Ontario baseline cut-points:
    • Physical Health and Well-Being - 7.31
    • Social Competence - 5.58
    • Emotional Maturity - 6.00
    • Language and Cognitive Development - 6.15
    • Communication Skills and General Knowledge - 4.38
  • When reporting results, areas with less than 15 EDI cases are suppressed or combined with other small areas that are geographically close and socioeconomically similar.


  • The teacher’s ability to complete the questionnaire based on his or her knowledge of a child’s development and well-being after six months of interaction may not accurately reflect the level of the child’s development.
  • The EDI is not a clinical diagnostic tool and is not intended to diagnose issues within an individual.
  • The EDI captures measures of school readiness at specific points in time and therefore causal associations cannot be determined.
  • The cut-points used to determine vulnerability can differ by region; therefore, caution should be used when comparing Peel results that use the Ontario Cycle 1 cut-points to other regions that do not use the same cut-point.


Last updated: February 12, 2019

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