Substantially all of the Company’s engagements are performed under time and materials or fixed-price arrangements. For time and materials contracts, the Company utilizes the practical expedient under Accounting Standards Codification 606 – Revenue from Contracts with Customers, which states, if an entity has a right to consideration from a customer in an amount that corresponds directly with the value of the entity’s performance completed to date (for example, a service contract in which an entity bills a fixed amount for each hour of service provided), the entity may recognize revenue in the amount to which the entity has a right to invoice.

The following table discloses the percent of the Company’s revenue generated from time and materials contracts:

	Fiscal Years
	2019	2018
Engineering & other scientific	66%	64%
Environmental and health	18%	18%
Total time and materials revenues	84%	82%

For fixed-price contracts the Company recognizes revenue over time because of the continuous transfer of control to the customer. The customer typically controls the work in process as evidenced either by contractual termination clauses or by the Company’s rights to payment for work performed to date to deliver services that do not have an alternative use to the Company. Revenue for fixed-price contracts is recognized based on the relationship of incurred labor hours at standard rates to the Company’s estimate of the total labor hours at standard rates it expects to incur over the term of the contract. The Company believes this methodology achieves a reliable measure of the revenue from the consulting services it provides to its customers under fixed-price contracts given the nature of the consulting services the Company provides.

The following table discloses the percent of the Company’s revenue generated from fixed price contracts:

	Fiscal Years
	2019	2018
Engineering & other scientific	15%	17%
Environmental and health	1%	1%
Total fixed price revenues	16%	18%

Deferred revenues represent amounts billed to clients in advance of services provided. During 2019, $5,754,000 of revenues were recognized that were included in the deferred revenue balance at December 28, 2018. During 2018, $6,067,000 of revenue were recognized that were included in the deferred revenue balance at December 29, 2017.

Reimbursements, including those related to travel and other out-of-pocket expenses, and other similar third-party costs such as the cost of materials and certain subcontracts, are included in revenues, and an equivalent amount of reimbursable expenses are included in operating expenses. Any mark-up on reimbursable expenses is included in revenues before reimbursements. The Company reports revenues net of subcontractor fees for certain subcontracts where the Company has determined that it is acting as an agent because its performance obligation is to arrange for the provision of goods or services by another party. The total amount of subcontractor fees not included in revenues because the Company was acting as an agent were $14,409,000 and $23,174,000 during 2019 and 2018, respectively.