Answer :
The correct answer would be, Sequential Methods of Research.
She would like to avoid the disadvantages associated with longitudinal and cross sectional research. I would suggest her to use the Sequential Methods of Research.
Explanation:
A sequential method of research is a method which use both the longitudinal and cross sectional designs of the research methods.
Longitudinal research method is a method in which the data is gathered from the same subject repeatedly over a period of time. Whereas, cross sectional methods include people who are different in their variable of interest but they have the some same characteristics like socioeconomic status, ethnicity, etc.
So if Dr. Robertson wants to avoid the disadvantages associated with the longitudinal and cross sectional method of research, she can use the sequential method, in which she can pick only the advantageous parts of the study, and can integrate the method in her research.
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