Answer: Standardization
Explanation:
Standardization is defined as process in which something is kept and followed as per basic standards of that field.It maintains consistency level in the field for all the factors.
According to the question, standardization is the drawback factor in Dr. Dodd's research because the measure of physical activity was based on standards of college student's field .
This standard is used by Dr. Dodd for measuring senior citizen's physical activity. Thus, the result obtained will be inaccurate because of incorrect standardization used.