Which type of bidding method may not require fully defined specifications?

The two-step sealed bidding process is particularly useful in situations where specifications are not entirely defined at the outset. This method encompasses two distinct stages: the first stage involves soliciting proposals based on general concepts or partial specifications to gauge the interest and capabilities of potential suppliers or contractors. After evaluating these initial proposals, the second stage seeks more refined bids based on the clarified specifications that emerge from the first stage.

This allows the procuring agency to engage with bidders in a way that can adapt to their feedback and innovations, ultimately leading to a more complete definition of the project requirements while still allowing for competitive pricing. Thus, the two-step sealed bidding method is advantageous when the complete details of a project cannot be specified at the outset, making it particularly effective for complex projects that require more interaction with vendors to outline the final requirements accurately.