System Usability Scale

SUS

stempsychologysocial sciencesFree for research use

A 10-item questionnaire giving a global view of subjective usability. Alternates positively- and negatively-worded items. Produces a single 0–100 score; 68 is commonly cited as the average.

Items

Response format

5-point Likert scale

Version

1.0

Ready-to-cite methods sentence

Perceived usability was measured using the System Usability Scale (SUS; Brooke, 1996), a 10-item instrument scored on a 5-point Likert scale. Item scores were transformed per Brooke's formula and summed, yielding a composite 0–100 SUS score (M = 68 is typical across systems).

Reliability & validation

notes

Meta-analytic α reported by Bangor, Kortum, & Miller (2008) across 2,324 surveys.

Validation population

Software users across many systems

Cronbach's α

0.91

Response anchors

Strongly disagree · Disagree · Neither agree nor disagree · Agree · Strongly agree

Known limitations

SUS produces a 0–100 score, not a percentage or percentile. Historically © Digital Equipment Corporation (1986); permissible for research use but commercial licensing varies. Substitute "system" with the product name when administering.

Original citation

Brooke, J. (1996). SUS: A "quick and dirty" usability scale., 189-194.

Use SUS in Folio Surveyor

Add it to a study with the full items, scoring, and analysis built in.

Open Surveyor

Library entry verified January 2024. Metadata is provided for reference; item wording is available inside Folio Surveyor, subject to each instrument's licensing.