ANNEX B.3 Usability resources: Frequently used usability questionnaires
This is a new questionnaire, designed to evaluate the quality of use of web sites. It is backed up by an extensive standardisation database, and it is purchased on a per report basis. It is the result of a joint development project by Jurek Kirakowski and Nigel Claridge.
This is a mature questionnaire, developed by John Brooke in 1986 and not published until years later. It is very robust and has been extensively used and adapted. It is public domain and nobody has published any standardisation data about it. Of all the public domain questionnaires, this is the most strongly recommended. The SUS is perhaps the most popular standardized usability questionnaire, accounting for approximately 43% of unpublished usability studies. It is a 10 item questionnaire designed to measure users’ perceived usability of a product or system. The SUS is highly reliable (.91) and is entirely free. To score the SUS, subtract the scale position from 1 on all oddly numbered items, and subtract 5 from the scale position on all evenly numbered items, then multiply the sum of all items by 2.5 to get an overall SUS score that ranges from 0-100.
This is a questionnaire developed by Kent Norman that has been modified many times to keep it current since its first appearance. It is commercially available and is championed by Ben Shneiderman in his book ‘Designing the User Interface’. Reading, MA: Addison-Wesley Publishing Co., 1998. Despite lack of standardisation and validation data, it has many adherents.
This questionnaire attempts to create a three-factor model of usability that can be applied to many situations. However, no reliability or validation data are presented. Public domain use is encouraged.
This is a well-designed questionnaire developed by Jim Lewis and it is public domain. It has excellent psychometric reliability properties but no standardisation base.
IsoNorm (in German only)
This questionnaire is designed to test the usability quality of software following the ISO 9241 part 10 principles. It is created by a team led by Jochim Puemper. Strong reliabilities are claimed for the sub-scales, although it appears there may be a strong inter-correlation between them as well. Downloads and an on-line version are available from the above URL, as well as articles about it (all in German.)
This questionnaire is produced by Guenter Gediga and his team. It is another attempt to produce a way of measuring ISO 9241 part 10, with reference to specific software features that may give rise to low usability data. It is therefore good both for summative and formative assessments. The questionnaire is well researched and detailed statistical information is given. Downloads of English and German versions are available. There is no standardisation base for it but it is public domain.
Post-Study Usability Questionnaire (PSSUQ)
The PSSUQ is a 16-item survey that measures users’ perceived satisfaction with a product or system. Obtaining an overall satisfaction score is done by averaging the four sub-scales of System Quality (the average of items 1-6), Information Quality (the average of items 7-12), and Interface Quality (the average of items 13-16). The PSSUQ is highly reliable (.94) and is entirely free.