A | | The final sample should be representative of the target population |
| 1 | At least 1 of the following should apply for the study (2 points) |
| | – An entire target population |
| | – Randomly selected sample |
| | – Sample stated to represent the target population |
| 2 | At least one of the following (2 points) |
| | – Reasons for nonresponders described |
| | – Nonresponders described |
| | – Comparison of responders and nonresponders |
| | – Comparison of sample and target population |
| 3 | Response rate > 90% (2 points) |
| | Response rate 70% to 90% (1 point) |
| | Response rate ≤ 70% (0 points) |
B | | Quality of data |
| 4 | Were the data primary from a prevalence study (2 points) or was it taken from a survey not specifically designed for that purpose (1 point)? |
| 5 | The same mode of data collection should be used for all subjects (2 points), if not: 1 point |
| 6 | – The data have been collected directly from the patient by means of a validated questionnaire/interview (3 points) |
| | – No validated questionnaire/interview patients (2 points) |
| | – Data have been collected from proxies or retrospectively from medical record (1 point). |
C | | General description of the method and results should include: |
| 7 | Description of target population and setting where patients were found (2 points) |
| 8 | Description of stage of disease, sex, age (all 2 points, 1 or 2: 1 point) |
| 9 | Final sample size (1 point) |
D | | Definition of FOG prevalence |
| 10 | Prevalence recall periods should be stated (1 point) |