In fact, many studies report outcomes in terms of 'treatment completers', which may artificially elevate reported rates of symptom alleviation (Albano and Kendall 2002).
In many studies of outcomes research, groups exposed to different practice patterns are compared.
In many studies, adverse outcomes remain more common among the infants of mothers with type 1 diabetes than in the general population [ 8, 29].
Many studies evaluating outcomes of cemented total hip arthroplasty in patients less than 30 years of age have shown poor results with high revision rates [ 18, 19].
Many studies combine outcomes of proximal tibial implants with those from other anatomic locations, including the distal and proximal femur [ 2, 5, 9, 20, 21, 26, 29, 31, 32, 38– 42, 44, 47, 49, 49, 51].
There are many studies reporting outcomes of ATT in HIV-infected patients with sputum smear and culture positive pulmonary TB [ 2, 10, 13- 15, 17- 19] but few including smear-negative and extrapulmonary TB [ 8, 9, 11, 12].
Altogether, our findings indicate that while operant performance for food in mice is relatively insensitive to many study parameters, experimental outcomes can be shaped predictably with proper design decisions.
Third, many studies measured subject outcomes using untried assessment tools that had been created on an ad hoc basis, and which may therefore have compromised measurement accuracy and inference validity.
In many studies, the outcome of skills training was measured on the trainer itself rather than during real surgery in the patient, and, thus, its value concurrent validity is in doubt.
As an example, many studies use outcome measures that produce continuous data, for which an ICC is needed to calculate sample size; this requires an a priori knowledge of within- and between- cluster variances [ 17].
