Answer to Question 1
In order to establish causality, three conditions must be present. First, if A is the causal variable under question, then A the cause and B the effect variables must be correlated. Second, A must precede B in time. Third, other potential causal variables, C, must be ruled out.
Answer to Question 2
Different types of research designs each can contribute different things to our understanding of causal relationships. A type of study called a cross-sectional design observes several cohorts (groups with similar defining characteristics) by taking a snapshot of them at a given point in time whereas longitudinal designs track cohorts over time taking multiple snapshots.
Tongue Conditions, Candidiasis (Thrush)
Patient conditions not appropriate for elctronic blood pressure measurement
Men Present for Service during the Civil War
Rank-order correlations show that differential consistency remains high from childhood through late ...
How to evaluate third-order determinants by Minors Method (Question 2)
Higher-Order Conditioning