Discuss the concept of validity, and describe internal and external validity

What will be an ideal response?

For research methods to have high validity, they must accurately measure characteristics that the researcher set out to measure. Methods that are implemented carelessly, unevenly, or inconsistently cannot possibly represent what an investigator originally intended to study. But to guarantee validity, researchers must go further. They often examine the content of observations and self-reports to make sure all behaviors of interest are included. Another approach is to see how effective a method is in predicting behavior we would reasonably expect it to predict. The concept of validity can also be applied more broadly: to the overall accuracy of research findings and conclusions.
In setting up an investigation, researchers must safeguard two types of validity. The first, internal validity, is the degree to which conditions internal to the design of the study permit an accurate test of the researcher's hypothesis or question. If, during any phase of the investigation—selecting participants, choosing research settings and tasks, and implementing procedures—participants' behavior is influenced by factors unrelated to the hypothesis, then the accuracy of the results is in doubt. Second, researchers must consider external validity, the degree to which their findings generalize to settings and participants outside the original study. Ensuring that samples, tasks, and contexts for conducting research represent the real-world people and situations that the investigator aims to understand is key to this type of accuracy.