What does it mean when a tool of assessment is characterized as reliable? Under what conditions might one expect an otherwise useful tool of assessment to be unreliable?  Consider the meaning of the following statement: “A test is valid.” How absolute or relative is test validity? Can a test be valid at one time and place with one population of testtakers and invalid at another time, in another place, or with another group of testtakers? 2 citations are needed at least 5 years old.