Design phase strategies for coping with confounders: Matching
Advantages
- Can eliminate influence of strong constitutional confounders like age and sex
- Can eliminate influence of confounders that are difficult to measure
- Can increase precision (power) by balancing the number of cases and controls in each stratum
- May be a sampling convenience, making it easier to select the controls in case-control study
Disadvantages
- May be time consuming and expensive, less efficient than increasing the number of subjects (e.g., the number of controls per case)
- Decision to match must be made at outset of study and can have irreversible adverse effect on analysis and conclusions
- Requires early decision about which variables are predictors and which confounders