Question

Describe and differentiate between internal and external threats to validity in an experimental design. Recommend at least one action that you or any researcher can take in response to both internal and external validity threats.

Answer 1

Internal threat to validity refers to the factors that can make the findings of the experiment less trustworthy and less reliable. Whereas External threat to validity refers to the factors that makes the finding of the experiment less generalizable to other situations.  

Examples of internal threats to validity : 1. confounding : a situation in which changes in an outcome variable can be thought to have resulted from some third variable that is related to the treatment that you administered.

2. MATURATION : refers to the impact of time as a variable in a study. If a study takes place over a period of time in which it is possible that participants naturally changed in some way (grew older, became tired), then it may be impossible to rule out whether effects seen in the study were simply due to the effect of time.

Examples of external threats to validity :  

1.Situational factors such as time of day, location, noise, researcher characteristics, and how many measures are used may affect the generalizability of findings.

2.Pre- and post-test effects refer to the situation in which the pre- or post-test is in some way related to the effect seen in the study, such that the cause-and-effect relationship disappears without these added tests.

Ways to avoid internal threat : 1. Ensure proper controlling of confounding variables

Ways to avoid external threat : 1. Carry out filed experiments outside the setting of laboratory.