Which type of contract allows a buyer to order products or services as needed over time, without known volume?

The correct answer is the call-off contract, which is designed to give flexibility to the buyer when ordering products or services over a specified period without committing to a fixed volume. This type of contract is particularly useful in situations where demand may be uncertain or sporadic, allowing organizations to draw down products or services as needed.

In a call-off contract, a supplier agrees to provide goods or services up to a certain pre-defined limit during the contract duration. This structure supports buyers in managing fluctuating needs without the obligation to purchase a set quantity upfront. It facilitates a more adaptable procurement process, where orders can be placed based on genuine requirements rather than forecasts.

The other types of contracts listed generally have different purposes. A purchase order is typically a document issued for a specific quantity of goods or services at a defined price, which doesn’t provide the same level of flexibility. A framework agreement establishes a long-term partnership and outlines the terms of supply without specifying exact quantities, yet it is not as flexible as a call-off contract in terms of placing orders. A service level agreement focuses specifically on the expected service performance and quality metrics, which does not relate directly to the ordering mechanism of products or services over time.