What are the differences between contracting by negotiation and sealed bidding?

Contracting by negotiation involves direct discussions between the buyer and potential contractors to reach an agreement, allowing for flexibility in terms and conditions. In contrast, sealed bidding requires contractors to submit their proposals in sealed envelopes by a specified deadline, with the bids publicly opened and evaluated based on predetermined criteria. Negotiation can lead to tailored solutions and adjustments based on feedback, while sealed bidding promotes transparency and fairness by treating all bidders equally. Ultimately, the choice between the two methods depends on the project's complexity and the desired level of interaction with bidders.