How can you control for internal and external validity?

Topic: the difference between external and internal validity in research

Assignment 1

Write a paper discussing the difference between external and internal validity in research. This should be written from the perspective of conducting only single subject research. Include the following, at minimum:

What is internal and external validity

How can you control for internal and external validity?

Is one more important than the other?

Helpful hints for setting up a research study (think: single subject researchoch only)