In a hypothetical cross-sectional study, marriage was found to be strongly associated with increased levels of happiness. Authors concluded that marriage was a cause of happiness. However, a reviewer of this study argued that because it is a cross-sectional study, it could not be determined whether marriage caused happiness or happiness caused marriage. What criterion of causal relationships was not met in the study according to the reviewer

The correct answer is - temporal relationship.

Explanation:

Temporal relationship is the timing between a variable or factor and an outcome or result that can be used to assign a reason for the relationship. This type of causal relationship that is temporal relationship cannot be assessed in a cross-sectional study.

As it can not be assessed in the cross-sectional study so, it is not possible to assess if happy people are more likely to get married or marriage leads to happiness.

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