????回想一下你上次讀過(guò)的商業(yè)管理書(shū)籍。它提供了什么樣的證據(jù)來(lái)支持自己的主張？是的，來(lái)自現(xiàn)實(shí)世界的案例可能富于啟發(fā)，但案例研究也有其局限性。我們需要知道它的局限性在哪里，不要被蒙蔽了。

????在很多商業(yè)管理書(shū)籍中，知名的成功企業(yè)，如西南航空（Southwest Airlines），往往被不厭其煩地細(xì)細(xì)剖析，試圖從中發(fā)現(xiàn)它們的成功之道。但種種說(shuō)法往往莫衷一是。西南航空的成功是因?yàn)楣緫?zhàn)略嗎？這當(dāng)然不無(wú)道理。那么換成企業(yè)文化呢？從很多方面來(lái)看，這種說(shuō)法也同樣有道理，雖然這種結(jié)論是基于完全不同的信息。會(huì)不會(huì)既是因?yàn)樗墓緫?zhàn)略，也是因?yàn)樗钠髽I(yè)文化？哦，對(duì)了，還有管理能力，如果從另外一個(gè)角度進(jìn)行分析，這個(gè)因素似乎也至關(guān)重要。如果哪樣看上去都很重要，我們?cè)趺粗缿?yīng)該最關(guān)注什么呢？

????這個(gè)問(wèn)題的產(chǎn)生就是因?yàn)檫^(guò)度地依賴(lài)案例研究來(lái)做結(jié)論，幾乎完全不考慮任何其他因素。仔細(xì)的分析的確能提供一些建議，幫助人們?nèi)〉媚撤N成果，或者避免某種后果。但如果我們忽視了案例研究的局限性就會(huì)碰到麻煩，下面我們將一一闡述常見(jiàn)的情形：

描述：發(fā)生了什么

????阿爾弗雷德?斯隆1963年出版的自傳《我在通用汽車(chē)的歲月》（My Years with General Motors）就是這方面的典范：有效的描述性案例研究離不開(kāi)詳盡的描述。斯隆在1923-1956年間曾任通用汽車(chē)（General Motors）總裁、首席執(zhí)行官和董事長(zhǎng)等多個(gè)職位，這本自傳從他的角度描述了他在通用汽車(chē)的角色以及他履職的原則。

????斯隆在這本書(shū)中沒(méi)有根據(jù)個(gè)人經(jīng)歷進(jìn)行任何總結(jié)歸納，也沒(méi)有亮出任何主張，他把這些留給了讀者。但他的記錄啟發(fā)了幾代經(jīng)理人和研究者，試圖總結(jié)出如果遇到像斯隆那樣的挑戰(zhàn)，應(yīng)該采取怎樣的行動(dòng)。

????如果我們的案例不是廣泛適用，我們的描述尺度最好不要超越斯隆。再次強(qiáng)調(diào)，暢銷(xiāo)的商業(yè)管理書(shū)籍往往會(huì)逾越這一界限。不排除有些例外，但總體而言，這些書(shū)大多具有下述兩大缺陷之一。

????其一是根據(jù)精心挑選的案例及由此派生出來(lái)的大量數(shù)據(jù)來(lái)證明一項(xiàng)理論，無(wú)視能驗(yàn)證理論可靠性的其他大量樣本。換言之，他們提供給我們的是“舉例來(lái)說(shuō)”，并非證據(jù)。其二，只研究精心挑選的案例，通常是表現(xiàn)最好的公司。這一點(diǎn)問(wèn)題尤其嚴(yán)重，因?yàn)闆](méi)有說(shuō)明案例與更廣大樣本之間的關(guān)聯(lián)，也就沒(méi)有充分的理由說(shuō)明選取的案例具有代表性。

解釋?zhuān)簽槭裁磿?huì)發(fā)生

????發(fā)生了什么是一碼事；理解背后的原因是另外一碼事。商業(yè)史學(xué)家大師阿爾弗雷德?錢(qián)德勒用案例研究幫助我們理解了多部門(mén)組織的出現(xiàn)。錢(qián)德勒在其具有開(kāi)創(chuàng)性的經(jīng)典著作《戰(zhàn)略與結(jié)構(gòu)》（Strategy and Structure）中重點(diǎn)談到了四家公司：杜邦（DuPont）、通用汽車(chē)、西爾斯（Sears）和標(biāo)準(zhǔn)石油（Standard Oil）?；谶@些研究，他得到了一組假設(shè)，這組假設(shè)經(jīng)受住了成百上千宗案例分析的無(wú)數(shù)次檢驗(yàn)，并支撐起了錢(qián)德勒的觀(guān)點(diǎn)——在足夠多元化的公司中，圍繞職能（會(huì)計(jì)、生產(chǎn)、營(yíng)銷(xiāo)）進(jìn)行公司架構(gòu)建設(shè)，不如圍繞市場(chǎng)進(jìn)行架構(gòu)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.