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Table 4 Content validity index of item relevancy and clarity, and Modified Kappa agreement of the Thumb Disability Exam (TDX)

From: Evaluation of the content validity index of the Australian/Canadian osteoarthritis hand index, the patient-rated wrist/hand evaluation and the thumb disability exam in people with hand arthritis

Item Relevance Clarity Interpretation
Agreement I-CVI* Pc** K*** Agreement I-CVI* Pc** K***  
A. Please indicate your ability to perform these activities with the affected hand
 Turn a Key 54/61 0.89 <  10 − 5 0.89 51/53 0.96 <  10 − 5 0.96 Excellent
 Pick up a coin 52/61 0.85 <  10 − 5 0.85 49/51 0.96 <  10 − 5 0.96 Excellent
 Write 56/61 0.92 <  10 − 5 0.92 51/54 0.94 <  10 −5 0.94 Excellent
 Squeeze toothpaste 52/60 0.87 <  10 −5 0.87 51/53 0.96 <  10 −5 0.96 Excellent
 Hold a glass of water 50/61 0.82 <  10 − 5 0.82 51/54 0.94 <  10 − 5 0.94 Excellent
 Turn a doorknob 52/61 0.85 <  10 − 5 0.85 51/53 0.96 <  10 − 5 0.96  
 Use a knife to cut food 54/61 0.89 <  10 −5 0.89 51/53 0.96 <  10 −5 0.96 Excellent
B. Please indicate your ability to perform the following task while using both your hands
 Open a jar 57/61 0.93 <  10 −5 0.93 50/51 0.98 <  10 −5 0.98 Excellent
 Button a shirt/blouse 53/61 0.87 <  10 −5 0.87 49/50 0.98 <  10 −5 0.98 Excellent
 Tie your shoes 55/61 0.90 <  10 −5 0.90 50/51 0.98 <  10 −5 0.98 Excellent
 Wring a dishcloth/washcloth 53/61 0.87 <  10 −5 0.87 49/51 0.96 <  10 −5 0.96 Excellent
II. The following questions refer to the level of pain in your thumb
 How often did you have pain in your thumb at rest? 50/61 0.82 <  10 −5 0.82 40/52 0.77 <  10 −5 0.77 Excellent
 How often did the pain in your thumb interfere with your daily activities? 49/60 0.82 <  10 −5 0.82 44/51 0.86 <  10 −5 0.86 Excellent
 How often did the pain in your hand interfere with recreational activities? 51/60 0.85 <  10 −5 0.85 44/52 0.85 <  10 −5 0.85 Excellent
 How often did the pain in your thumb interfere with your sleep? 47/60 0.78 <  10 −5 0.78 44/52 0.85 <  10 −5 0.85 Excellent
 How often did the pain in your thumb worsen your mood? 51/60 0.85 <  10 −5 0.85 42/52 0.81 <  10 −5 0.81 Excellent
III. The following questions ask about your satisfaction with the indicated hand or thumb over the past week.
 Motion in your affected thumb 48/58 0.83 <  10 −5 0.83 47/53 0.89 <  10 −5 0.89 Excellent
 Strength of your affected hand 54/57 0.95 <  10 −5 0.95 48/53 0.91 <  10 −5 0.91 Excellent
 Pain level of your affected hand 52/58 0.90 <  10 −5 0.90 48/53 0.91 <  10 −5 0.91 Excellent
 Overall function of your hand 53/58 0.91 <  10 −5 0.91 46/52 0.88 <  10 −5 0.88 Excellent
S-CVI 0.87 (95% CI: 0.85to 0.89)   0.91 (95% CI: 0.89to 0.94)   
  1. NOTE: *I-CVI: item-level content validity index, **pc (probability of a chance occurrence) was computed using the formula: pc = [N! /A! (N -A)!] *.5N where N = number of raters and A = number of raters who agree that the item is relevant or clear, ***K (Modified Kappa) was computed using the formula: K = (I-CVI- PC)/(1- PC). Interpretation criteria for Kappa, using guidelines described in Cicchetti and Sparrow (1981): Fair = K of 0.40 to 0.59; Good = K of 0.60 to 0.74; and Excellent = K > 0.74. I-CVI, item-level content validity index; scale-level content validity index, average (S-CVI/Ave)