1 Overview of internal validity

So far, you have learnt to ask a RQ, identify different ways of obtaining data, and design the study.

In this chapter, you will learn how to ensure that the conclusions we can make are logical and sound. You will learn to:

  • identify issues that might impact internal validity.
  • identify issues that might impact the values of the response variables.
  • identify extraneous, confounding and lurking variables.