Generalisability = Could you apply this research/theory to anyone anywhere in the world?
Reliability = Could you do this research again and again, and get the same results? Is there anything which could be influencing the results?
Validity = Is the research testing what it actually said it would test? Are the findings “true”?
Ethics = Are there any ethical issues with the theory/research? Could it cause physical or psychological harm to someone? Could it have negative implications?
Application = Can this research/theory be applied to real life scenarios? Could it make a difference in everyday life?