Cronbach’s Alpha: Reliability

Cronbach’s alpha in R with the psych package — measure the internal consistency of a questionnaire or scale.

Do the items on a scale hang together and measure one thing?

Run the code

Everything in the video — edit it and press Run Code to run real R right here, or copy it:

Note

The first Run Code installs the packages this lesson needs (psych) into your browser session — give it 20–40 seconds.

Download this R script  ·  ▶ Open the full playground

When to use it. Use it to assess a multi-item scale’s internal consistency; values above ~0.7 are usually acceptable. Remember to reverse-key negatively worded items.

Read Cronbach’s alpha in R.

Next: Sample Size & Power →