Reliability refers to the consistency in responses or test scores. A test is said to be reliable if a person answers consistently over multiple occasions. If the results of a test are close or identical after administering the test numerous times the test is said to be reliable. A test that is administered twice and provides different answers is not reliable and should not be trusted. An example of reliability is a scale used to determine one’s weight. If you stepped on the scale two times back to back, you should get the same weight. If the scale gave you two different weights, it would be unreliable. There are two common types of reliability (internal and external). Internal reliability examines the consistency of results across items on a test. External reliability examines how much a measure varies from one use to another. We will discuss the types of validity below. Two terms commonly used together are reliability and validity. However, while these terms are commonly used together, they are different. Validity will be discussed later. However, it is important to remember that just because a test is determined to be reliable does not mean it is valid.