The article explores how mergers influence productivity in industries. The researchers created a model to study how mergers, new companies joining, and existing ones leaving affect efficiency. They found that mergers can boost the average firm's productivity by 4.8%. This improvement comes from both the combined strengths of merged companies (4.1%) and how mergers impact the decisions of firms entering or exiting the industry (0.7%). The research suggests that policies promoting the entry of new businesses may have a different impact on productivity when the influence of mergers is taken into account.