Ordinal scales and foundations of misinference

Area of Science:

• Rehabilitation Medicine
• Biostatistics
• Health Outcomes Research

Background:

• Functional assessment scales are in high demand within the rehabilitation community.
• There is a need for reliable measures of patient function that reflect treatment impact.
• Current evaluation instruments may not be optimally suited for tracking treatment progress.

Purpose of the Study:

• To examine the fundamental deficiencies of ordinal scales in providing information for logical inference.
• To analyze the constraints ordinal scales impose on assessing treatment progress.
• To investigate the rationale behind clinical decision-making based on commonly used functional assessment scales.

Main Methods:

• Critical analysis of the informational content of ordinal scales.
• Examination of the logical inferences derived from ordinal scale data.
• Review of the underlying principles guiding clinical decisions based on functional assessment instruments.

Main Results:

• Ordinal scales possess inherent limitations that restrict the scope of valid inferences, particularly concerning treatment efficacy.
• Overlooking these scale deficiencies can result in substantial practical and economic repercussions.
• The suitability of some widely used instruments for measuring treatment-induced functional changes is questionable.

Conclusions:

• The limitations of ordinal scales necessitate a cautious approach to interpreting patient progress in rehabilitation.
• A deeper understanding of scale properties is crucial for accurate clinical decision-making and resource allocation.
• Further development or selection of assessment tools that better capture functional changes is warranted.