The mantra taught to me was "Go wide, go narrow, go specific"
Go wide = the literature review to show you have read widely and researched all the options and considerations
Go narrow = either start to reduce the number based on either (a) your arguments or (b) the findings of your primary research e.g. questionnaires or observations from within your group or organisation
Go specific = your conclusion based on the evidence you have presented and your arguments
Good luck
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