Cost-reimbursement contracts are appropriate when the work has substantial uncertainty or technical risk, and the government reimburses allowable costs with a fee. This approach recognizes that total costs and even the exact scope may not be knowable at the outset, such as in research and development or complex engineering work where requirements evolve or new information emerges. The contractor is paid for actual allowable, allocable costs incurred, plus a fee to provide incentive and profit. Because the government bears the cost risk, there must be rigorous oversight, cost reporting, and audit rights to ensure costs are allowable and reasonable and that they align with the contract terms. If the work is well-defined with low risk, a fixed-price contract is usually better because it establishes a firm price and shifts most cost risk to the contractor. For simple, small tasks, fixed-price is also typically more efficient. When the contractor bears most of the cost risk, that tendency points to fixed-price arrangements, not cost-reimbursement.