1. How can the error margin impact the results of psychological assessments?

2. When considering test/re-test reliability, it is not the repeated testing that is important, it's the repeated results. In other words, test/re-test reliability means that a test can be administered numerous times and still yield the same results. In stats terms, the correlation between test scores from different administrations must be high. A general rule of thumb is r ≥ 0.8 (this depends on the test, of course).

Here's an example:

I've worked for Pearson Education scoring the SAT for (ahem) over 20 years. When I took the SAT in high school, I achieved a perfect score (that's how I came to work for them). Every few years, I re-take it as part of Pearson's quality control process: will the test produce the same results over time? Granted the details of the questions change (face validity), but what that test is tapping into (content validity) remains the same. Thus the high test/re-test reliability score.

3. What is the importance of validity in psychological testing?

4. What is the difference between reliability and validity? Please incorporate the following concepts into your response:

Test/re-test reliability
Internal consistency
Face validity
Content validity

Additionally, why is it important to consider reliability and validity in psychological testing?

5. Suppose a test has good test/re-test reliability, but poor face validity. How can this be rectified? Should it be rectified? Is poor face validity that much of an issue? Why or why not?

6. What is the importance of face validity within psychological testing?