Usability requirements: how to specify, test and report usability


This web site provides a guide for how to specify and test usability requirements as part of a contractual relationship between a supplier and acquirer. It includes case studies of four trials carried out in Europe by the EU-funded PRUE project.

Common Industry Format for usability test reports

A new Common Industry Format for documenting usability results has been developed by a US-based group of companies coordinated by NIST. (For more information see the IUSR web site.). The format has been approved as an American standard (ANSI/NCITS-354-2001), and is intended to be submitted to ISO.

Case studies

The EU-funded PRUE project demonstrated the value of using the Common Industry Format in four case studies applied to different situations: public and private contracts for development of a web site, and acquisition of a travel management system and travel agency software.

Serco worked with the Italian Ministry of Justice to introduce usability requirements into in the acquisition of a new legal information web site, and SUA worked with Ericsson to introduce usability requirements in the procurement of an office software product.

Loughborough University and SIEM used the CIF to evaluate the effectiveness of an existing system to assess its acceptability and the need for improvements as part of a contractual relationship with a supplier. Loughborough assessed an online shopping website, and SIEM assessed travel agency software


Incorporating usability requirements in the procurement process can reduce the risk of failure when implementing a newly acquired system and increase ease of use and thus productivity and/or profitability.

  • Lack of user performance requirements was a fundamental reason for the expensive costs and delays incurred when new passport issuing software developed by Siemens was installed in the UK [12].
  • Two studies have shown that the user success rate in purchasing from current ecommerce web sites is in the range of 25-60% [9,12]. Small improvements in user performance could lead to substantial increases in revenue.

Defining requirements for user performance and satisfaction is not difficult to do, and involves three related activities: analysing the context of use, defining task scenarios, and specifying testable requirements for effectiveness, efficiency and satisfaction for each scenario. Evaluating usability requirements needs a carefully designed usability test with at least 8 representative users carrying out realistic tasks.

Copyright © 2002 Serco Ltd. Reproduction permitted provided the source is acknowledged.