The Contribution of Mergers to Industrial Concentration: A Reply to Professor Prais
回应普雷斯教授对作者先前研究的批评，指出其抽样方法虽有偏差但已尽力最小化，并重申并购对两次世界大战期间产业集中度增长贡献的下限估计为50%。
1. We agree that there are possible biases in our sampling procedure. Any calculations based on imperfect historical data and limited samples are subject to error. The job of constructive research is not simply to cry 'bias', but to seek to minimize it and to estimate its likely effects. This we have done. Professor Prais offers no quantitative estimate of the significance of the issues to which he refers. He correctly points out that we acknowledge that our sampling procedure may have led to some upward bias. He fails to mention that there is also an opposite source of bias, in that concentration increase resulting from mergers we have failed to detect is attributed to internal growth. We can only reiterate (a) that our lower bound estimate of the contribution of merger to inter-war concentration growth, based on systematic resolution of uncertainties in a direction favourable to Professor Prais' case, is 50%/, (b) that if we could somehow ascertain the 'true' answer to this question we do not think it substantially more likely that it would lie below rather than above our present estimates.