General methodological limitations, including sampling methodology, retrospective study design, and terminology, have been discussed previously [ 2].
Several methodological limitations, including preexperimental design approaches, limited control of confounders and small sample sizes burden this body of evidence.
Although the literature advocated early ambulation, the evidence base presented with a number of recurrent methodological limitations, including small sample sizes, lack of a control sample, and limited follow-up.
Existent research is plagued with methodological limitations including inattention to selection effects and reliance on mostly cross-sectional designs.
The current evidence base presented with a number of methodological limitations, including not randomising patients to group allocation, permitting allocation bias [23], and not blinding assessors to subject groups, therefore increasing the risk of assessment bias [24].
However, studies examining these associations have been subject to methodological limitations, including cross-sectional designs, retrospective measures, a lack of stress biomarkers, and the tendency to overlook momentary etiologic processes occurring within each day.
Methodological limitations included small sample sizes limiting the power of the tests, and reliability of the effect estimation (hazard ratio+regression coefficients).
Methodological limitations included sampling and measurement biases, inadequate internal validity of measurement tools, poor specification of testing protocols and limitations in statistical analysis.
Methodological limitations include the fact that sleep duration was self-reported.
Methodological limitations include the predominance of quasi-experimental, pre-post designs, and case studies.
Other methodological limitations include small study sizes, potential misclassification of exposure, recall biases and inadequate adjustment for potential confounders.
