In our case, 'causation' was determined by considering the interaction between contexts (i.e., the circumstances and settings of guideline use), mechanisms (i.e., the processes operating within guidelines that explain why they are used in some circumstances but not in others) and outcomes (whether guidelines are used or not).
While some might argue that the Watkins et al study proves reverse causation, a single study cannot result in such a conclusion, just as forward causation cannot be determined from a single study.
The directionality of causation cannot be determined from sequence data alone.
Furthermore, our study had a case control design, thus direct causation cannot be determined.
The cross-sectional nature of these studies should again be emphasized since causation cannot be determined due to potential confounding of the study results.
According to Hill [ 50], causation can be determined using the temporal relationship, which implies that the cause of a disorder must precede its clinical signs.
The results were difficult to interpret, however, because the temporal sequence of causation could not be determined.
We found patterns of association between adverse life events and at-risk alcohol use, and specifically events indicating interpersonal and financial adversity, although the direction of causation could not be determined from this cross-sectional analysis.
As a number of studies were not longitudinal, and many faced institutional barriers to entry and data collection, causation could often not be determined.
Even if they were exempt from natural causation, they would still be determined by God's will, and so would be unfree.
Two possible scenarios are still open: (1) entangled pairs exchange some form of superluminal information (and energy) below the limits of Heisenberg's uncertainty relations; or (2) causation may be symmetrical so that the direction of causation in a physical system is determined by its boundary conditions.
