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about 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 and 2010, 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 across the province in three-year cycles.
  • EDI questionnaires were completed by senior kindergarten teachers in all publicly funded schools for all the senior kindergarten kids in their class in the second half of the school year.
  • Students that were in the classroom and taught by the teacher for at least one month were included in the assessment.
  • The EDI questionnaire is available in English and French.
  • The EDI tool contains 104 questions, 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:
  • Physical Health and Well-being
  • Social competence
  • Emotional maturity
  • Language and cognitive development
  • 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 to a group level.
  • Each EDI domain is scored from 0 to 10 with scores closer to 10 indicating more advanced levels of school readiness but, the distribution of scores is different for each domain.
  • Different classifications are based on certain percentile cut-points; "vulnerable" defined as a child whose score is at or below the 10th percentile, "at risk" are those from the 10th to the 25th percentile, "ready" are those from 25th to the 75th percentile, and "very ready" are children who score from the 75th percentile for each EDI domain. Ontario Cycle 2 cut-points were used in Peel in 2010.
  • 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.


  • Teacher ability to complete the questionnaire based on his/her knowledge of student's development and well-being of a student 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 2 cut-points to other regions that do not use the same cut-point.


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