Revenue Recognition CRA derives substantially all of its revenues from the performance of professional services. The contracts that CRA enters into and operates under specify whether the engagement will be billed on a time-and-materials or a fixed-price basis. These engagements generally last three to six months, although some of CRA's engagements can be much longer in duration. Each contract must be approved by one of CRA's vice presidents. CRA recognizes substantially all of its revenues under written service contracts with its clients when the fee is fixed or determinable, as the services are provided, and only in those situations where collection from the client is reasonably assured and sufficient contractual documentation has been obtained. In certain cases CRA provides services to its clients without sufficient contractual documentation, or fees are tied to performance-based criteria, which require CRA to defer revenue in accordance with U.S. GAAP. In these cases, these amounts are fully reserved until all criteria for recognizing revenue are met. CRA's revenues include projects secured by our non-employee experts as well as projects secured by our employees. CRA recognizes all project revenue on a gross basis based on the consideration of the criteria set forth in Accounting Standards Codification ("ASC") Topic 605-45, Principal Agent Considerations . Most of CRA's revenue is derived from time-and-materials service contracts. Revenues from time-and-materials service contracts are recognized as services are provided based upon hours worked and contractually agreed-upon hourly rates, as well as indirect fees based upon hours worked. Revenues from the majority of CRA's fixed-price engagements are recognized on a proportional performance method based on the ratio of costs incurred, substantially all of which are labor-related, to the total estimated project costs. CRA derived approximately 15%, 13%, and 15% of consolidated revenues from fixed-price engagements in fiscal 2014, fiscal 2013, and fiscal 2012, res