Hypothesis 4c, of a positive effect of sabbaticals on perceived autonomy, cannot be tested in this meta-analysis, because no primary study analyses this effect.
The available systematic reviews of aggregate data are compromised because the primary studies report both adjusted and unadjusted estimates.
One could argue that the conceptual innovation, in this case, was only necessary because the primary studies did not address our review question directly.
Cochrane reviews in palliative care are well performed, but fail to provide good evidence to guide clinical practice because the primary studies are few in number, small, clinically heterogeneous, and of poor quality and external validity.
Second, the effects of the type of diabetes on the association between the polymorphism and DR were not addressed because the primary studies did not provide the relevant data.
Cochrane reviews in palliative care are well performed, but fail to provide good evidence for clinical practice because the primary studies are few in number, small, clinically heterogeneous, and of poor quality and external validity.
We also acknowledge that further quantification of degree of exposure to tuberculosis cases, including proximity to the index case and the number of cases in close contact, was not possible in our study because the primary studies were not designed to compare exposure in children who were and were not immunised with BCG.
Because we selected primary studies included in systematic reviews, we were unable to test the coverage of articles that some physicians find relevant (studies of lower methodological quality, narrative reviews, case reports, animal studies, commentaries etc).
Of these, six were excluded because they were planned studies, four were excluded because the focus groups were Internet-based, three were excluded because they were not primary studies and seven were excluded because they did not, in fact, report the results of focus group studies even though the term "focus groups" appeared in their abstracts.
We did not include any studies of testosterone inhibiting drugs because all identified controlled primary studies had high overall risk of bias.
