By reading the literature we come to know that "No" research has been undertaken in the specified area, This is "The Gap".
The following literature can be refereed for the identification of Gaps:
Articles(Having Pure Theory)
Papers ( Have Data)
Journals and Conference proceedings
Thesis
Dissertations
The result of the literature survey is the identification of Research gaps. In this way, we have identified the problem.
identifying a problem means finding the variable.
The variable is the characteristics that can change with respect to person, place, or time.
Variables can be :
Continuous variable or Discontinuous variables
Independent variables or Dependent variables
intervening variables (intrinsic or Extrinsic)
Concomitant variables (Variables which are in the process but doesn't affects the dependent variables in the presence of independent variables)