Question

1. Can you think of any other threats to internal validity that are unique in the world? If so, give an example.

2. Give an example in which regression toward the mean might occur?

Thank you for your help.

Answer 1

History, maturation, selection, mortality and interaction of selection and the experimental variable are all threats to the internal validity of this design.

A research article might be an example,

Threats to the Internal Validity of Experimental and Quasi-Experimental Research in Healthcare:

The article defines, describes, and discusses the seven threats to the internal validity of experiments discussed by Donald T. Campbell in his classic 1957 article: history, maturation, testing, instrument decay, statistical regression, selection, and mortality. These concepts are said to be threats to the internal validity of experiments because they pose alternate explanations for the apparent causal relationship between the independent variable and dependent variable of an experiment if they are not adequately controlled. A series of simple diagrams illustrate three pre-experimental designs and three true experimental designs discussed by Campbell in 1957 and several quasi-experimental designs described in his book written with Julian C. Stanley in 1966. The current article explains why each design controls for or fails to control for these seven threats to internal validity.