Significant Developmental Delay (SDD)

Identification of Children with Significant Developmental Delays (SDD)

According to the Wisconsin Administrative Code (PI 11.36 (11)), Significant developmental delay means children, ages 3, 4 and 5 years of age or below compulsory school attendance age, who are experiencing significant delays in the areas of physical, cognition, communication, social—emotional or adaptive development....

Issue Update

  • The IDEA Amendments of 1997 allowed states and LEA’s (local education agencies) the option to apply the term Significant Developmental Delay to include children experiencing developmental delay ages 3 through 9 years.
  • The Council for Exceptional Children – Division for Early Childhood (CEC-DEC) recommends that a developmental delay category of eligibility be available for all children from birth through age 8.
  • 23 states have extended the age range for SDD beyond age 5 according to the National Early Childhood Technical Assistance Center (NECTAC).
  • Wisconsin is one of 2 states with a proposed rule change that would increase the upper age range for SDD.
  • One major reason cited in support of extending the age range is to minimize miscategorization that can result from inaccurate or inappropriate assessment given that many of the standardized and norm-referenced assessment tools for young children have limited reliability.
  • One major criticism associated with expanding the SDD age range is the potential increase in prevalence rates for SDD.
  • The counter point to this criticism is that while there may be an increase in SDD prevalence rates; conversely, there may be a decrease in prevalence rates in more restrictive categories such as EBD, CD, LD and OHI. There is a need for more research and data analysis in this area.
  • The SDD category in "Wisconsin Feasibility Study: Extending the Age Range" (2005) concluded with recommendations to extend the age range for SDD through age 8.
  • Public hearings to consider changes in the eligibility criteria for SDD were conducted during September and October of 2007. Comments have been summarized. Until statutory changes are made, the current rule and guidance remains in effect.
  • An update to the 2005 Feasibility Study is being planned and will include longitudinal data analysis of Wisconsin data, data from states that have extended the age range through age 8 or 9 and interviews with the state directors of special education in these states, and a review of current developmental delay policies and recommended practices.
  • The updated feasibility study will conclude with recommendations based on all additional information including a review of current policy, recommended practices, and longitudinal data.
  • The projected timeline for the updated study is the 2009-2010 school year.


The SDD eligibility checklist was developed in 1998 and provides guidance for the current regulations. Word Fillable Version

Executive Summary of Feasibility Study, September 2005

Summary of Public Hearing Comments (link to be added)

Information Update Bulletin 97.01

Eligibility Policies and Practices for Young Children Under Part B of IDEA, NECTAC