Assessment of Learning Disabilities

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Thinking and Reasoning Abilities

assessment of learning disabiilties - Children with LD

assessment of learning disabiilties – Children with LD (image source :

Measures utilized to assess thinking and reasoning abilities should meet the requirements of standardized, individually-administered, psychometrically-sound, psychological test instruments, be supported by appropriate research, and interpreted by appropriately-trained psychological service providers.

There are times when deficits in specific psychological processes mask normal functioning in more general thinking and reasoning abilities, making an accurate assessment of global intellectual ability difficult. It is important to note that a diagnosis of a learning disability does not always require an individual’s global intellectual ability (e.g., full-scale IQ) to fall in the average range or above. In such cases other estimates of thinking and reasoning abilities independent of the underlying processing impairment (such as a relevant index, component, or composite score, or other combination of appropriate subtest scores) can be taken as evidence of average functioning in these areas, provided these results are supported by evidence and interpreted with sound clinical judgment.

In addition, there may be individuals for whom the tools currently in use do not fully demonstrate their cognitive strengths. For these cases, real world situations may need to be investigated as a part of a complete assessment in order to demonstrate cognitive abilities.

Examples of currently available appropriate test instruments are contained in the supporting documentation.

Psychological Processes Related to Learning

It is mandatory to document performance in one or more of the following areas that is significantly and reliably below the levels predicted by obtained measures of thinking and reasoning outlined above:

  • Phonological Processing
  • Memory and Attention
  • Processing Speed
  • Language Processing
  • Perceptual-Motor Processing
  • Visual-Spatial Processing
  • Executive Functions

It is also necessary that statements related to such deficits in psychological processes are based on more than one source of information, and that they be logically related to the observed learning difficulties. It should be noted that a number of different professionals may be involved in this part of the assessment, with the relevant results being incorporated in the final documentation of the learning disability by the regulated health care professional qualified to communicate the diagnosis.

Academic Achievement

The parent, teacher, and student themselves may be in a position to provide critical information about past and present academic successes and challenges, as well as the level of support provided to reach current levels of academic functioning.

It is mandatory to document under-achievement or achievement sustained by extremely high levels of effort or support in one or more academic areas (as evident in the classroom and in standardized test results) and to relate academic performance to underlying deficits in specific psychological processes. In most cases there will be evidence of a significant disparity between cognitive potential and measures of achievement in academic areas. In circumstances where there has been an extremely high level of effort and support, there may not be a significant disparity between cognitive ability and academic achievement.

The academic assessment measures should be individually administered, standardized tests. Canadian norms should be used wherever they are available. Where Canadian norms are not available, caution should be exercised when interpreting standardized scores. Measured achievement levels should, however, be consistent with the individual’s observed on-going performance and areas of weakness Comprehensive testing should be undertaken in observed areas of weakness, assessing all components of identified skills wherever possible. For example, if reading is identified as an area of weakness, assessment should include measures of decoding,
comprehension, reading fluency, oral vocabulary, etc.

Age-equivalents and grade-equivalents should not be used as a basis for comparison between tests, due to their imprecision. It is considered best practice to compare standard scores from co-normed tests, using proper statistical procedures.