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Learning Disabilities Diagnostic Inventory

Donald D. Hammill, Ed.D.
Brian R. Bryant, Ph.D.


The LDDI inventory helps professionals identify learning disabilities in children ages 8 to 17, and reveals the extent to which skill patterns in a particular area (e.g., reading or writing) are consistent with those of individuals known to have a learning disability in that area (e.g., dyslexia or dysgraphia). The LDDI can be completed in 10 minutes by a teacher or speech-language pathologist who is familiar with the student’s skills.

The LDDI inventory is composed of six independent scales, each with 15 easy-to-rate items. Stanines are used to identify the likelihood of intrinsic processing disorders in the six areas—Listening, Speaking, Reading, Writing, Mathematics, Reasoning—as well as to conduct a profile analysis to determine the extent to which a student’s LDDI profile reflects that which is associated with learning disabilities. The inventory was normed on 2,152 students with learning disabilities and reports scores in stanines and percentiles.
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Scales & Forms

  • Listening 
  • Speaking
  • Reading
  • Writing
  • Mathematics
  • Reasoning
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Donald D. Hammill, Ed.D.
Brian R. Bryant, Ph.D.

Age Range 8 to 17 years

Administration Time 10 to 20 minutes

Administration Type Client-completed

Qualification Level B

  • Handscored