| MEASUREMENT PROPERTIES | |
| Limitations | >=5 European languages (English) |
| Observations | |
| 1. RELIABILITY | |
| A. Internal Consistency | Tested |
| Cronbach's (Describe) |
Cronbach's alpha was >0.9 in all the age groups ( 20-30 years, 30-40 years, 40-50 years and 50-60 years) indicating excellent internal consistency of the items on the scale in all the age groups. |
| B. Reliability intraobserver or test-retest | Tested |
| Continuous scores: intraclass correlation coefficient (ICC) Dichotomus: Cohen kappa (Describe) |
In a sample of 120 independent limbs, across different age groups, IdFAI demonstrated overall excellent test-retest reliability (ICC 2,1 = 0.959). Similar results were also obtained by Simon and Donahue in their study (ICC 2, 1 = 0.92) done on 110 independent limbs. |
| C. Reliability interobserver or Measurement error | Tested |
| Standard error of measurement (SEM), smallest detectable change (SDC) or Limits of agreement (LoA) (Describe) |
The reliability of scale was found to be excellent across all age groups ranging from 20-60 years. The study demonstrates that IdFAI can accurately predict if an individual meets the minimum criterion for FAI across different age groups. Thus, the questionnaire can be applied over different age groups in clinical and research set-ups. It is also important to determine whether the IdFAI will classify participants as either having FAI or not having FAI in a similar manner on different days .On the first day of testing, 30 participants were identified as having FAI, and on the second day, 34 participants were identified. Seven individuals changed status (FAI or no FAI) between the 2 test days, and their scores varied 1 or 2 points. The study also showed that between the two test occasions, there was exact agreement for 95 (79.16%) participants, and an additional 25 (20.84%) participants differed by only 1 or 2 points. |
| 2. VALIDITY | |
| A. Content validity: face validity | Not Tested |
| Expert opinion (relevance and comprehensiveness) (Describe) |
|
| B. Construct Validity: Structural validity |
Not Tested |
| Hypotheses-testing | Tested |
| Cross-cultural validity | Tested |
| Brief Description | |
| C. Criterion validity | Tested |
| Comparison with a 'gold standard' Continuous scores: correlations, ROC curves Dichotomus: Sensitivity & Specificity (Describe) |
The IdFAI had an accuracy of 89.6%. The IdFAI had an overall prediction rate of 87.8%, a calculated sensitivity of 0.83 (CI: 0.75; 0.89) and specificity 0.94 (CI: 0.89, 0.97). |