A fifth ground of validity is that the success rate of treatment in the present study (75% in the short-term) is similar to that 75-800%) reported in TMD textbooks [ 29- 31].
A second ground of validity is that the VAS-scores of pain intensity become residual in the long-term in patients whose treatments were successful according the TDC-criterion.
A third ground of validity is that the increased utility values of EQ-5D (a variable that is independent from TDC) in patients whose treatment is successful (mean 0.917 units), corresponds to a self-rated global health of a general population sample that is 'good' to 'very good' [ 28].
Despite obtaining an α below the minimum cutoff, the decision was made to retain awareness of NHS screening programmes on the grounds of content validity.
This indicates that they are well-known symptoms and analyses using them as single-item variables would have limited usefulness; however, they were included on the grounds of face validity.
24 Although RCTs are often considered the gold standard of trial design due to their ability to minimise the impact of selection and information biases, control for confounding variables and potentially rule out chance, they have often been challenged on the grounds of external validity.
The choice of general population setting (as opposed to patient cohorts in clinical settings) coupled with a sampling approach that aims to derive a representative sample of a defined reference population are often justified on the grounds of external validity [ 5].
Because the numerator for a given area records immunizations of children who have consumed a service located in that area, and the denominator estimates the number of children served, in theory, by that area's services on grounds of residency, the validity of coverage indicators depends on the extent to which the attraction and catchment areas overlap.
Teacher D also had issues with the listening test on the grounds of its apparent face validity and a lack of proper equipment for giving a listening test.
The significance of this study was challenged by Brabin [ 3] on the grounds of inconclusive statistical differences and validity issues.
