商业案例研究滥用成灾

    回想一下你上次读过的商业管理书籍。它提供了什么样的证据来支持自己的主张？是的，来自现实世界的案例可能富于启发，但案例研究也有其局限性。我们需要知道它的局限性在哪里，不要被蒙蔽了。

    在很多商业管理书籍中，知名的成功企业，如西南航空（Southwest Airlines），往往被不厌其烦地细细剖析，试图从中发现它们的成功之道。但种种说法往往莫衷一是。西南航空的成功是因为公司战略吗？这当然不无道理。那么换成企业文化呢？从很多方面来看，这种说法也同样有道理，虽然这种结论是基于完全不同的信息。会不会既是因为它的公司战略，也是因为它的企业文化？哦，对了，还有管理能力，如果从另外一个角度进行分析，这个因素似乎也至关重要。如果哪样看上去都很重要，我们怎么知道应该最关注什么呢？

    这个问题的产生就是因为过度地依赖案例研究来做结论，几乎完全不考虑任何其他因素。仔细的分析的确能提供一些建议，帮助人们取得某种成果，或者避免某种后果。但如果我们忽视了案例研究的局限性就会碰到麻烦，下面我们将一一阐述常见的情形：

描述：发生了什么

    阿尔弗雷德•斯隆1963年出版的自传《我在通用汽车的岁月》（My Years with General Motors）就是这方面的典范：有效的描述性案例研究离不开详尽的描述。斯隆在1923-1956年间曾任通用汽车（General Motors）总裁、首席执行官和董事长等多个职位，这本自传从他的角度描述了他在通用汽车的角色以及他履职的原则。

    斯隆在这本书中没有根据个人经历进行任何总结归纳，也没有亮出任何主张，他把这些留给了读者。但他的记录启发了几代经理人和研究者，试图总结出如果遇到像斯隆那样的挑战，应该采取怎样的行动。

    如果我们的案例不是广泛适用，我们的描述尺度最好不要超越斯隆。再次强调，畅销的商业管理书籍往往会逾越这一界限。不排除有些例外，但总体而言，这些书大多具有下述两大缺陷之一。

    其一是根据精心挑选的案例及由此派生出来的大量数据来证明一项理论，无视能验证理论可靠性的其他大量样本。换言之，他们提供给我们的是“举例来说”，并非证据。其二，只研究精心挑选的案例，通常是表现最好的公司。这一点问题尤其严重，因为没有说明案例与更广大样本之间的关联，也就没有充分的理由说明选取的案例具有代表性。

解释：为什么会发生

    发生了什么是一码事；理解背后的原因是另外一码事。商业史学家大师阿尔弗雷德•钱德勒用案例研究帮助我们理解了多部门组织的出现。钱德勒在其具有开创性的经典著作《战略与结构》（Strategy and Structure）中重点谈到了四家公司：杜邦（DuPont）、通用汽车、西尔斯（Sears）和标准石油（Standard Oil）。基于这些研究，他得到了一组假设，这组假设经受住了成百上千宗案例分析的无数次检验，并支撑起了钱德勒的观点——在足够多元化的公司中，围绕职能（会计、生产、营销）进行公司架构建设，不如围绕市场进行架构更有效率。

    Consider the last business book you read. What kind of evidence did it provide to support its claims? True, examples from the real world can be illuminating, but case studies have their limits. You need to know what those limits are to avoid getting duped.

    In many management books, apparently successful companies, like Southwest Airlines (LUV), are dissected ad nauseum in an attempt to discover what makes them tick. Yet the many different accounts often disagree. Is Southwest recognized because of its strategy? That's certainly a plausible view, but what about its culture? That is in many ways an equally compelling position, although one based on very different information. Could it be because of its strategy and its culture? And, oh yes, its leadership, an attribute that seems critical when the company is viewed from yet another perspective. When everything seems important, how are we supposed to know what to focus on?

    This problem comes from an over-reliance on case studies to make conclusions, almost to the point of excluding other types of evidence. Careful observation can offer recommendations that might help you repeat -- or avoid -- a particular result. But we run into problems when we don't take into account the limitations of case studies, which are as follows:

Description: What happened

    Alfred Sloan's 1963 book My Years with General Motors is representative of just how careful you need to be in order for a descriptive case study to be useful. Having served as president, CEO, and chairman of General Motors (GM) in a few different combinations from 1923 to 1956, Sloan's book provided his perspective on his role at the company and the principles he used to fulfill that role.

    Sloan leaves it to the reader to draw generalizations beyond his experiences, and is careful to make no claims to underlying or enduring insights. His observations, however, have inspired generations of managers and researchers as they have sought to specify ways to cope with challenges similar to the ones Sloan confronted.

    For descriptions to go beyond the constraints of Sloan's approach, we must be sure that the cases are broadly applicable. Once again, popular business books typically overreach on this front. There are some worthwhile exceptions but, in general, most of these books show one of two deep flaws.

    One is to illustrate a theory that is based on lots of data with carefully chosen cases, but leave the larger population that justifies the theory invisible. In other words, we are offered "for instance" instead of proof. The second is to examine only carefully chosen outliers, usually high-performing firms. This is especially problematic since, without showing any connection between the sample and some larger population, there is no good reason to conclude that the sample is representative of anything other than itself.

Explanation: Why it happened

    What happened is one thing; understanding why it happened is something else. Alfred Chandler, one of the great business historians, used case studies to help us understand the emergence of the multi-divisional organization. He focused on four companies: DuPont (DD), General Motors, Sears (SHLD), and Standard Oil in his seminal classic Strategy and Structure. Out of that research emerged a set of hypotheses that have been tested and found valid hundreds of times in hundreds of subsequent case studies, which have supported Chandler's idea that in sufficiently diverse companies, organizing around business functions (accounting, production, marketing) is less effective than organizing around markets.