For any paper or thesis, a hypothesis or problem statement needs to be made. The best ones are those that provide the following information:
The population doesn't need to be human. Most often this is a problem or process that needs to be changed in some way.
Current practice, opposing viewpoints, or conditions under which P & I occur
Measuring what worked best
The hypothesis or problem statement is not searched completely as stated. Most searches will focus on the problem (P) and the Improvement (I). When a comparison of two ways of doing things (C) is needed, that part becomes the 3rd concept in your search strategy. The results or outcome is not part of the search strategy.
To get up to speed on your topic you need the "who, what, where, when, why or how"
Who or What equals Population, Problem, or Process
How or Why equals Intervention, Investigation, or Improvement
Where or When equals Comparison or conditions of what you are studying