The Oswestry low back pain disability questionnaire (ODQ) contains 10 questions that have 5-point Likert scale answers and can measure the response to therapy.^[1]

• The ODQ questions are worded to reduce recall bias^[2].
• The minimal clinically important differences (MCID) has been proposed as >0.5 standard deviation improvement.^[3]
• MCID of 12.8 has been proposed^[4]
  • Copay et al used various methods to determine the optimal MCID^[4].
    • Receiver-operating characteristic curve derived MCID: ” The optimal cut-off value for a ROC curve corresponds to the point of optimal trade-off between sensitivity and specificity “
    • Half a standard deviation: Template:Sfrac \times {SD}
    • Standard error of measurement SD \times \sqrt{1 – r}, “where SD is the standard deviation of the baseline scores and r is the test-retest reliability coefficient”
    • Minimum detectable change: 1.96 \times \sqrt{2} \times{SEM}
    • Effect size derived MCID: “multiplying the SD of the baseline scores by 0.2 (the small effect size)”

Copay calculated the MCID to be 12.8^[4]. Davidson recommends an MCID of 10.5 or 15^[5].

Fritz calculated a value for the MCID of 6.^[6]

Vianin’s literature review finds the range of MCIDs proposed is 4 to 10.5.^[7]

• Treatment outcome

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