Explain what is meant my validity and reliability

Broadly speaking, validity refers to accuracy whereas reliability refers to consistency.

There are many types of reliability and validity, I few of which I have explained here:

- Internal validity is the extent to which the measurement or study is accurate within itself.

E.g. Does this particular self report accurately measure the participants’ anger?

- External validity is the extant to which the conclusions of the study can be generalised beyond the original study and participants.

I.e. can we generalise the conclusions of this study with these particular participants to other situations?

- Internal reliability is the extent to which a measurement or a study is consistent within itself.

E.g. if we were to split the the participants in half and give them the same test, would the results of both halves be similar?

- External reliability is the extent to which the results and conclusions of a study are consistent over time.

I.e. if we repeated the same study over time, would we obtain the same results?

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I would be happy to help you apply these definitions to examples in your study when you’re evaluating in exam questions.

E.g. Bandura’s study lack may external validity because all the children were from the same nursery school in America. We can’t generalise the results of this study to children outside this nursery as we can’t assume that all children will imitate behaviour in the same way. Therefore, it lacks external validity because we can’t generalise the conclusions to this study to all children.