Panel assessment: each expert grades the question over a range from 1 to 4, with 1 not relevant and 4 very relevant.
Parameters:
(1) number of experts on the panel
(2) number of experts who grade a question as 3 or 4 (quite relevant or very relevant)
content validity index =
= (number of experts who grade a question 3 or 4) / (number of questions)
Interpretation:
• minimum index: 0
• maximum index: 1
• A question is adequate if the index is >= 0.80.
Some authors also refer to a CVI for the entire instrument (S-CVI). Different authors have different ways of determining this, with parameters the number of items in the instrument and the item CVI:
(1) mean CVI (average agreement)
(2) decimal fraction of items that have an index of 1 (universal agreement)
(3) decimal fraction of items that are >= 0.80.
