This article references a published 'Performance Work Statement' (PWS) that has been issued by the United States Marines and is available in the public domain.
At a strategic level (i.e. the Board) a decision may be taken to engage third party suppliers to assist with the introduction of ITIL into the organization. The production of a 'Performance Work Statement' (PWS) or a 'Statement of Work' (SOW) is used as the mechanism to convey to prospective suppliers the requirements of the initiative, project or program.
The following link provides an example of an actual Performance Work Statement for an Information Technology Service Management Process Improvement Initiative, which has been published by the United States Marines and is currently available in the public domain. In addition it also incorporates a 'Quality Assurance Surveillance Plan' (QASP), which is used to evaluate the performance of the supplier with regards the delivery of the PWS.
Unfortunately the document has been removed and we are currently seeking an alternative source of information.