In their study of substance use and family formation, Jang, Patrick, and Schuler (2017) specifically state that cigarette use, marijuana use, and the amount of binge drinking are all defined as happening at least once in the last 15–30 days. The importance of these specifications would be considered an issue of . . .
a. operationalization
b. level of measurement
c. conceptualization
d. mutual exclusivity
e. unobtrusive measurement
