The quality of being accurate; does the test measure what it's supposed to measure?
Validity
The quality of being consistent; does the test give the same results every time?
Reliability
Based on personal feelings or opinions rather than facts.
Subjective
To identify a problem or illness by examining the symptoms.
Diagnose
To measure something and express it using numbers.
Quantify
In psychology, a detailed questionnaire or test to measure something like interests.
Inventory
A person's natural ability or potential to do something in the future.
Aptitude