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