11. 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. 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 a majority of the Company'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.

Revenues also include reimbursable expenses, which include travel and other out-of-pocket expenses, outside consultants, and other reimbursable expenses. Reimbursable expenses are as follows (in thousands):

	Quarter Ended

	March 30, 2013		March 31, 2012
Reimbursable expenses	$	7,658	$	8,297

CRA collects goods and services and value added taxes from customers and records these amounts on a net basis, which is within the scope of ASC Topic 605-45, "Principal Agent Considerations."