Table 3. Calculating of CVR for a sample of instrument items at the first round of judgment.
| Items | N e * | CVR ** | Interpretation |
| 1 | 9 | 0.0667 | Remained |
| 2 | 5 | -0.333 | Eliminated |
| 3 | 10 | 0.3333 | Eliminated |
| 4 | 15 | 0.8667 | Remained |
| 5 | 9 | 0.2 | Eliminated |
| 6 | 13 | 0.6 | Remained |
| 7 | 7 | -0.2 | Eliminated |
| 8 | 7 | -0.067 | Eliminated |
| 9 | 13 | 0.6 | Remained |
NOTE: * Number of experts evaluated the item essential, **CVR or Content Validity Ratio = (Ne-N/2)/(N/2) with 15 person at the expert panel (N=15), the items with the CVR bigger than 0.49 remained at the instrument and the rest eliminated.