Table 3 Item-level content Validity Index (I-CVI) and Average Deviation from the Mean Index (AD_M) of OHIP-14 K instruction, response format, event frequency, and items in the Clarity and Equivalence Indices

Original Scale Element (back-translation of OHIP14-K)

I-CVI

AD_M

I-CVI

AD_M

Instruction

0.9

0.38

0.3

0.55

Response Format

0.7

0.34

0.8

0.63

Event Frequency^a

1.0

0.40

0.6

0.54

1. Trouble pronouncing any words

1.0

0.40

0.6

0.96

(Discomfort from not being able to pronounce well)

2. Sense of taste has worsened

1.0

0.38

0.7

0.64

(Sense of taste was worse than before)

3. Painful aching in your mouth

1.0

0.40

0.4

0.70

(Pain in the tongue, sublingual, cheeks, palate, etc.)

4. Uncomfortable to eat any foods

1.0

0.39

0.7

0.60

(Uncomfortable to have meal due to painful or uneasy problems of the mouth)

5. Self-conscious

0.9

0.38

0.4

0.56

(Reluctant to meet others because of shame)

6. Felt tense

0.9

0.38

0.6

0.54

(Paid attention to)

7. Unsatisfactory diet

1.0

0.40

0.9

0.48

(Dissatisfied meals)

8. Meals interrupted

1.0

0.40

0.8

0.36

(Interrupted during meals)

9. Difficult to relax

1.0

0.39

0.8

0.36

(Difficulties resting comfortably)

10. A bit embarrassed

0.9

0.39

0.9

0.36

(Embarrassed or perplexed)

11. A bit irritable with other people (Get angry easily at others)

0.9

0.37

0.5

0.70

12. Difficulty doing your usual jobs

0.9

0.37

0.9

0.56

(Difficult to do normal jobs)

13. Life in general was less satisfying

0.9

0.37

0.8

0.54

(Life less satisfying than before)

14. Totally unable to function

0.8

0.36

0.6

0.72

(Psychologically, physically and socially cannot at all do one’s share)