Answer: Meta-analysis
Step-by-step explanation:
Meta-analysis is the statistical analysis combination of results from multiple scientific studies. It's usefulness can be seen when multiple research is done on the same question which various individual or researchers bringing the results of their study. Its a quantitative and epidemiological study design applied to systematically assess results from previous research in order to get a conclusion from them all to drive a conclusion.
This is the research strategy Dr. Grayson is using