1.9 Descriptive vs. causal research questions
- Q: What is the difference?
1.9.1 Descriptive questions
- How are observations distributed across values of Y? (univariate)2
- e.g. How are individuals (observations) distributed across values of trust?
- How are observations distributed across values of Y and X?
- How are observations distributed across trust and gender values?
- We can add as many variables/dimensions as we like
- How are observations distributed across trust, gender and time values?
- Normally we summarize those distributions using models (associational inference)
- e.g. means of trust across gender across time
1.9.2 Causal questions
- Is there a causal link between the distribution across values of Y and values of D?
- Do differences in D cause differences in Y? (see app)
- Would individual i have another level trust (Y), had he not been victimized (D)?
- …in practice we tend to summarise those distributions..
- Continuous variables: Compare means
- Categorical variables (several): Compare probabilites for categories
* Q: How do I calculate the mean? * The mean of trust for non-victims is 6.2, the mean of trust for victims is 5.48.