to put variables into practice by making them measurable
making sure procedures used in research are the same for every participant to ensure the jnternal validity of the study
Whether the results are caused by the variables being studied, not by something else.
Whether the results can be generalised beyond the study. (ecological and population validities)
Can findings apply to real-life settings for example using a real life task not sometjing you would never do in real life
Can findings be generalised to other groups of people for example across cultures, genders, ages and races
Whether findings are still true over time.
