Measurement Error
How might random error and systematic error influence the measurements you make? This tutorial provides a discussion of the difference between these two sources of measurement error as well as how it might be reduced.
Reliability and Validity
This site reviews what is meant by "reliability" and "validity" in a measure.
Types of Reliability
Learn more about the types of reliability, including some that are not discussed in the text.
Measurement Validity
Is a particular measure "valid?" This site provides a tutorial to help you differentiate between the different types of validity pertinent to instrument construction.
