|Principles of causality|
|Strength||the stronger the association, the more likely is causality*|
|Consistency||the association exists in different contexts and times|
|Specificity||the association is specific for the variable and one particular outcome*|
|Temporality||the variable precedes the outcome*|
|Dose–response relationship||an increase in the variable results in an increase in the outcome*|
|Plausibility||plausible theories/mechanisms for explaining the association exist*|
|Coherence||the causal theory is coherent with existing knowledge|
|Experimental manipulation||manipulation of the variable results in changes in the outcome*|
|Analogy||similar associations exist between different variables|
Principles marked with an * are the principles discussed in the text.
Meijer et al.
Meijer et al. BMC Medicine 2013 11:130 doi:10.1186/1741-7015-11-130