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Table 3 Step difficulties represented with logit unit of the ODI with 6-level scaling

From: Measurement precision of the disability for back pain scale-by applying Rasch analysis

Item δ i 1 δ i 2 δ i 3 δ i 4 δ i 5 Disordering of the step difficulties (*)
       1–2 2–3 3–4 4–5
ODI 1: Pain intensity −2.61 −1.34 0.99 0.86 1.62    *  
ODI 2: Personal care −0.19 −0.62 0.96 2.01 2.02 *    
ODI 3: Lifting −2.65 −0.16 −0.94 −1.01 2.30   * *  
ODI 4: Walking −1.67 −0.40 0.02 0.95 2.38     
ODI 5: Sitting −1.08 −0.99 −0.01 1.36 2.40     
ODI 6: Standing −2.36 −0.99 −1.12 0.14 1.94   *   
ODI 7: Sleeping −1.35 0.82 0.91 1.33 1.35     
ODI 8: Sex life −1.26 0.44 −1.34 0.16 0.39   *   
ODI 9: Social life −1.48 −1.03 −0.47 0.67 1.46     
ODI 10: Traveling −2.01 −0.72 0.39 −0.48 0.42    *  
  1. δ, thresholds: the measure ability in the equally probable of two successive responses.
  2. δ i 1: indicates the threshold belonging to the first and the second responses.