Deferred-acceptance auctions are a type of auction that have strong incentive guarantees and can be implemented efficiently. In this paper, the researchers looked at how well these auctions perform in terms of maximizing social welfare in different auction scenarios. They found that for knapsack auctions, deferred-acceptance auctions outperform other similar mechanisms. In combinatorial auctions with single-minded bidders, new mechanisms were designed that combine the incentive guarantees of deferred-acceptance auctions with close-to-optimal results.