Question

In scientific investigations, researchers must clearly define the variables under study by precisely describing how they will be measured or controlled. These definitions are referred to as​

Answer 1

I believe the answer is: operational definitions

Operational definition refers to the statement that is used to describe/explain how a set of data is obtained. The purpose of this definition is to help other experts who review the research during the validation process, to determine whether the conclusion that the researchers made is wrong or correct.