Postpartum modern contraceptive use in northern Ethiopia: prevalence and associated factors - methodological issues in this cross-sectional study

Comment on: Complement C3 and fatty liver disease in Rheumatoid arthritis patients: A cross‐sectional study

“…Regardless of the results obtained from the model, it should be explained that accurate predictors or determinants of a dependent variable cannot be reliably identified by a cross-sectional study because predictors must be identified based on cohort studies. [2][3][4] In other words, predictive or causal inferences cannot be made from cross-sectional studies because of the associations between variables measured at the same time point in such studies. Without the temporality assumption, there is no way of determining whether a factor is a risk factor, is predictive/causal or is a consequence of the outcome.…”

Comment on Favorable association of polyphenol-rich diets with lung function: Cross-sectional findings from the Moli-sani study

“…Without longitudinal data, it is not possible to establish a true cause and effect relationship. In other words without the temporality assumption there is no way of determining whether a factor is a risk factor, is predictive/ causal, or is a consequence of the outcome, therefore, longitudinal studies are essential for developing assumptions to be used in clinical prediction models [2][3][4][5].…”

Role of physical activity in mortality prediction in elderly hospice patients: the methodological issues

“…Misleading results are generally the main outcome of research that fails to validate its prediction models ( Rothman et al, 2008 ; Sani et al, 2016 ; Sabour, 2017 ). And also, without the temporality assumption (the dependent variable must occur after the independent variable) there is no way of determining whether a factor is a risk factor, is predictive/causal, or is a consequence of the outcome ( Hanis et al, 2017 ; Mansori et al, 2017 ). Therefore, longitudinal studies are essential for developing assumptions to be used in clinical prediction models, whereas in this study, a cross-sectional study was used to identify the independent predictors for mortality prediction in elderly hospice patients.…”