In an increasingly data-driven world, it is more important than ever for students as well as professionals to better understand basic statistical concepts. 100 Questions (and Answers) About Statistics addresses the essential questions that students ask about statistics in a concise and accessible way. It is perfect for instructors, students, and practitioners as a supplement to more comprehensive materials, or as a desk reference with quick answers to the most frequently asked questions.

# What Are the Different Types of Reliability, and When Are They Used?

### What Are the Different Types of Reliability, and When Are They Used?

There are four types of reliability. Each has a particular purpose, and most use some form of the correlation coefficient to establish a numerical index of reliability.

Test-retest reliability examines the stability or consistency of a test over a period of time. It is ideal for establishing the level of reliability of a test that is given on two different occasions.

Parallel forms reliability examines the stability or consistency of a test when the test comes in two different forms. It is ideal for establishing the level of reliability for two forms of the same instrument.

Internal consistency reliability examines whether a test consistently assesses the same dimension or construct. It is ideal for establishing ...