These methods focus on different emphases.The two pre vailing methods are the method based on abnormal return and the method based on performance improvement following mergers.

• 这些方法从不同的角度出发衡量协同效应 ,其中发展得比较成熟的是在异常收益的基础上计算协同效应 ,以及从业绩改变角度着手衡量协同效应。