Research 2.0访谈
三思而行:迈克尔·莫布森访谈录
Think Twice: An Interview with Michael Mauboussin
史蒂夫·韦特——2009 年 11 月 9 日 波士顿 | 纽约 | 巴黎
Steve Waite – Novemer 9, 2009 Boston | New York | Paris
史蒂夫·韦特和克里斯·塔特尔——2009 年 10 月 XX 日
Steve Waite and Kris Tuttle – October XX, 2009
以下是我们对迈克尔·莫布森的采访。他是波士顿 | 纽约 新近出版的《哈佛商业出版社 | 再思考:利用反直觉的力量》一书的作者,目前担任美盛资本管理公司的首席投资策略师。希望您像我们一样喜欢这次采访和这本书。
Below is an interview we conducted with Michael Mauboussin, author of the recently Boston | New York published book|Think Paris Twice: Harnessing the Power of Counterintuition (Harvard Business Press), and Chief Investment Strategist at Legg Mason Capital Management. We hope you enjoy the interview and book as much as we did.
恭喜您的新书问世!克里斯和我读得津津有味。我们觉得,与其为《三思而后行》写篇书评给读者,不如通过访谈和您一起探讨书中的一些内容。感谢您在百忙之中抽出时间与我们交流。
Congratulations on your new book! Kris and I thoroughly enjoyed it. Rather than write a book review of Think Twice for our readers, we thought it might be better to explore some of the material with you in an interview. We appreciate you taking time out of your busy schedule to spend time with us today.
MM谢谢,史蒂夫。能跟各位在一起,我真的很开心。
MMThanks, Steve. It’s really a pleasure to be with you.
你能给我们简要概述一下这本书的内容是什么,以及是什么启发你写了它吗?
Can you give us a quick synopsis of what the book is about and what inspired you to write it?
MM这本书的核心观点是,当人面对某些特定类型的情境时,大脑会本能地按一种方式去思考,但实际上存在一种更好的思考方式。你的思维被引向某条具体却错误的路径,这可能导致糟糕的决策。
MMThe basic idea of the book is that when you are faced with certain types of situations, your mind will naturally think about it one way when there is a better way to think about it. That your mind takes you down a specific, and incorrect, path can lead to poor decisions.
让我给你举一个极其简单的数学问题作为例子:
Let me give you an incredibly simple math problem as an example:
一个球棒和一个球总共 1.10 美元。球棒比球贵 1.00 美元。球多少钱?
A bat and a ball together cost $1.10. The bat costs $1.00 more than the ball. How much does the ball cost?
如果你是个普通人,你要么回答了 0.10 美元,要么 0.10 美元是你脑子里冒出来的第一个数字。正确答案当然是 0.05 美元。回答 0.10 美元几乎是下意识的反应。你得再想一遍才能避开这个答案。
If you’re a normal person, you either answered $0.10 or $0.10 was the first number that came to mind. The right answer, of course, is $0.05. Answering $0.10 is basically automatic. You need to think twice to avoid it.
这个问题属于心理学家肖恩·弗雷德里克设计的认知反射测试中的三道题之一。我最近在演讲中经常问起这道题,它确实有效地说明了《三思而后行》这本书的核心主题。
This question is one of three that comprise the cognitive reflection test, devised by a psychologist named Shane Frederick. I have been asking this question in my talks lately, and it definitely illustrates the main theme of Think Twice effectively.
我为什么写这本书?和你一样,我花了很多时间思考、讲授和亲身实践投资决策的过程。这些年有一件事变得非常清楚:成为优秀投资者的关键,和电子表格的关系远没有和思考能力的关系大。然而,商学院教的东西绝大部分是交易的技艺——估值、策略、组合结构等等。别误会,这些东西确实重要。但真正让伟大投资者与众不同的,不是 Excel 模型,而是他们的思维方式。《三思而后行》这本书,就是试图帮助所有专业决策者在职业生涯的这个层面上有所提升。
Why did I write the book? Well, like you, I have spent a lot of time thinking about, teaching, and practicing the process of investment decision making. And one of the things that has become very clear to me over the years is that the key to being a great investor is a lot less about spreadsheets than it is about thinking well. Yet the vast majority of what we teach in business school is the trade of investing—valuation, strategy, portfolio structure, etc. Don’t get me wrong, those things are important. But what distinguishes the great investors is not the Excel models, but their mental processes. Think Twice is an effort to help all professional decision makers in that facet of their career.
你在书里说,在概率性的环境中,关注做决策的过程而不是结果,对我们更有利。这话说得一点没错。你能多谈谈这在投资中的应用吗?
In the book, you say that in a probabilistic environment, we are better served by focusing on the process by which we make a decision than on the outcome. That seems right on the money. Can you talk about this a little more as applied to investing?
MM首先我要说,我理解为什么人们都盯着结果。结果很客观、经得起审计,也是我们计分的方式。所以,沉溺于结果确实很诱人。
MMFirst off, let me say I understand why people are focused on outcomes. Outcomes are objective. They are audited. And they are how we keep score. So it is very tempting to dwell on outcomes.
但在概率性领域,好的决策可能导致糟糕的结果——反之亦然——此时关注结果就找错了方向,因为你无法知道自己是否因为正确的理由而做对了事。
But in fields that are probabilistic, where a good decision can lead to a poor outcome—and vice versa—a focus on outcomes is misplaced, because you don’t know if you were right for the right reason.
让我说得更具体一些。标准的二十一点策略告诉你,手牌加起来到 17 点时就应该停牌。这条规则来自概率研究;换句话说,在大量局数中,17 点停牌比继续要牌的结果更好。但这并不意味着那些选择要牌的人偶尔不会拿到一张 4。在这种情况下,运气帮了他们一把。而你知道,如果他们在 17 点时每次都选择要牌,他们的结果会比每次都停牌的人糟糕得多。
Let me be more concrete. Standard blackjack strategy says you should sit on cards that add up to 17. That rule comes from a study of probabilities; in other words, over many trials you’ll be better off sitting on a 17 than asking for a hit. But that doesn’t mean that people who ask for an additional card don’t get a 4 from time to time. In that case, luck has made their hand. And you know that if they always ask for a hit while sitting on a 17, they’ll be much worse off than someone who always sits on the hand.
所以,在任何涉及概率的事情里,你都应该聚焦于一个经济上合理的流程,并且坚信,长期坚持好的流程,才最有可能带来好的结果。但你也必须承认,即便遵循了正确的流程,结果也可能因为天意难测的运气而令人失望。
So in any probabilistic endeavor, you want to focus on an economically sound process, with the conviction that over time a good process provides the best chance for a good outcome. But you also need to acknowledge that even if you follow the right process, the outcomes will be unfavorable due to the inherent nature of chance.
在书的一开始,你提到没有背景的信息会让人产生虚假的自信。读到这句话时,我想到了所有那些 CNBC 的观众,他们试图在三十分钟或一小时的节目里获取股票建议和投资思路。每个片段里,大量信息被抛出,但背景信息却很少——在我看来这很危险,就像你所说的,虚假的自信。能谈谈你的看法吗?
Early on in the book, you observe that information without context is falsely empowering. When I read that I thought about all the CNBC viewers trying to pick up stock tips and investment ideas during a 30 minute or one hour program. There’s a lot of information thrown out during any one segment, but very little context, which seems dangerous to me – falsely empowering, as you put it. Can you comment on this?
MM哇,这一题分量很重。我脑海里立刻冒出两个想法。
MMWow, this is a big one. Two thoughts come immediately to my mind.
第一点是,当面临决策时,大多数人会自然而然地进入信息收集模式。他们花在思考自己面对的是哪种类型问题上的时间少得可怜。这可能导致一种虚假的自信心。
The first is that when faced with a decision, most people naturally go into information-collection mode. They spend a depressingly little amount of time thinking about the type of problem they face. This can lead to a false sense of confidence.
书的第一章主题提供了一个例证:过度依赖“内部视角”而非“外部视角”。采用内部视角时,你会收集信息,并利用这些信息以及你掌握的其他独特输入,来预测未来的结果。这是人们自然而然的运作方式——无论他们正在考虑翻新厨房、推出新产品,还是思考股市的可能回报。
One illustration comes from the theme of the book’s first chapter, which is an inappropriate reliance on the “inside” versus the “outside” view. With the inside view, you gather information and use that information, along with your other unique inputs, to project outcomes in the future. This is the way people naturally operate, whether it’s contemplating a renovation to their kitchen, launching a new product, or thinking about the likely returns from the stock market.
与之相对,“外部视角”把某个问题视为一个更大参照系中的实例。换句话说,它会问一个确实很简单的问题:当其他人处于这种情况时,发生了什么?所以,外部视角通过提供基准概率数据,为你的决策补充了某些关键背景信息,这些数据极具价值且非常有用。
The outside view, by way of contrast, looks at a problem as an instance of a larger reference class. In other words, it asks a really simple question: when other people were in this situation, what happened? So the outside view contributes some crucial context to your decision by providing base rate data that can be very informative and useful.
第二条思考涉及理论的应用。有一种模式令人沮丧地普遍存在:
The second thought relates to the application of theory. Here’s a pattern that’s depressingly common:
研究人员研究一家近期取得成功的公司,从中提取出一些特质,然后宣称这些特质是每家公司成功的关键。换句话说,研究人员试图把在一个情境中起作用的做法,硬塞进所有情境。我的书架上摆满了揭示“真正管用的方法”或“成功七把钥匙”的书籍。这些书大多纯属胡扯,但销量很好,因为它们告诉人们想听的话:“只要你做到以下几点,就能成功。”生活哪有这么简单。
Researchers study a company that has recently enjoyed success, extract some attributes from that company, and suggest that those attributes are the keys for every company to succeed. Stated differently, researchers try to cram what’s worked in one situation into all situations. My bookshelf is filled with books that show “what really works” or the “seven keys to success.” Most of these are totally bogus. But they sell well because they tell people what they want to hear: “If you do the following, you will succeed.” Life is not so easy.
我们来谈谈人们在决策过程中经常犯的一些错误。你那本书里到处都是这种例子。你在华尔街和商界最常看到的是哪些错误?
Let’s talk about some of the mistakes people routinely make in their decision making process. Your book is full of them. What are the ones you see most frequently on Wall Street and in the business world?
没错,我之前提到内部视角和外部视角的区别,这确实是个重要议题。我的同事比尔·米勒最近写过一篇文章,举了个例子来说明这一点。目前华尔街的主流看法是“新常态”,也就是——
MM: I mentioned the inside versus outside view, and that’s a big one. My colleague Bill Miller recently wrote about an example that makes the point. It seems that the consensus on Wall Street is the “new normal,” that
未来的经济增长率将因多种原因而放缓。这是从内部视角得出的判断。但外部视角会问:预测 GDP 增长复苏幅度的最佳方法是什么?经济学家对此已有较为深入的研究,答案是:看衰退的幅度。而我们刚刚经历了几十年来最剧烈的下滑之一。
future rates of economic growth will be slower for a host of reasons. That’s the inside view. But the outside view would ask: what’s the best way to predict the magnitude of the recovery in GDP growth? Well, economists have studied this in some detail and the answer is: the magnitude of the decline. And we’ve just come off one of the sharpest drops in decades.
一条与历史衰退和后续复苏相匹配的回归模型显示,2010 年 GDP 增长率为 8% 至 9%。而当前市场共识是 2.4%。这差距相当大。我当然不会说 2010 年一定能达到 8% 的增长,但外部视角或许会让人倾向于认为,增速更可能快于市场共识,而非慢于共识。
A regression that fits past declines with subsequent increases places 2010 GDP growth at 8-9 percent. The current consensus is 2.4 percent. That’s a heck of a gap. Now I certainly wouldn’t argue for 8 percent growth in 2010, but the outside view may incline one to believe growth is more likely to be faster than consensus than slower.
另一个常见错误是未能理解技能和运气在结果中各自扮演的角色。在任何一个技能与运气并存的系统中,你都会看到均值回归现象。投资者在做决策时并不擅长考虑均值回归。
Another common mistake is the failure to understand the contributions of skill and luck in outcomes. In any system that combines skill and luck, you will see reversion to the mean. Investors are not good at considering mean reversion in their decision making.
我在书中给了一个例子,依据的是两位金融学教授的研究。他们花了十多年时间,研究了超过 3200 家计划发起人——这些人按理说是最精明的投资者——在雇佣和解雇基金经理时的决策。这些发起人倾向于雇佣那些此前跑赢基准的基金经理,解雇那些跑输基准的。但正如均值回归所预示的那样,他们发现,被解雇的基金经理在决策之后的两年里,业绩反而超过了新雇佣的基金经理。这又回到了你之前问的那个关于过程与结果的问题。人们——即便是那些理应更明白的人——确实很难避免过于关注结果。
I provide an example in the book that was based on research by a pair of professors of finance. They studied the decisions to hire and fire money managers of over 3,200 plan sponsors—supposedly the most sophisticated of investors—over a decade. The sponsors tended to hire managers who had outperformed their benchmarks in the preceding period and to fire those who had underperformed. But, as mean reversion would predict, they found that the fired managers outperformed the hired managers in the two years subsequent to the decision. It goes back to your question before about process and outcome. It’s really hard for people—even those who should know better—to avoid focusing too much on outcomes.
你在书的第三章提到了一个概念叫“专家挤压”(expert squeeze)。听起来这个现象背后酝酿着某种重要变化——给我们详细讲讲吧。
You have a term in chapter three of your book called the expert squeeze. Sounds like something important is going on here, tell us more about it.
MM核心思想是,在众多决策场景中,专家正逐渐丧失作用——一边是计算机或算法,另一边是集体或群体的智慧。当然,这两者背后都有一个巨大的共同驱动力:技术。计算能力与社交网络软件的进步,让我们能借助更多方法来解决问题。
MMThe basic idea is that experts are losing their usefulness in a lot of decision-making settings to computers, or algorithms, on the one side and to collectives, or the wisdom of crowds, on the other. And of course there’s a big, common driver in both cases: technology. Advances in computing power and social networking software are allowing us to tap more methods to solve problems.
我再补充两点。首先,重要的是要认清算法或群体智慧何时能发挥作用。我提供一个连续谱系:一端是结果范围有限、基于规则的问题,这是计算机大显身手的领域。例如,计算机可以梳理企业收集的庞大客户数据,揭示出有用的模式。Netflix 的 Cinematch 程序——通过算法为观众匹配 DVD 影片——就是一个绝佳范例。显然,在提供优质推荐方面,Cinematch 比任何专家的表现都要好得多。
Let me add a couple of points. First off, it’s important to recognize when either algorithms or crowds will be effective. I offer a continuum. On the one side are problems that are rules based with limited ranges of outcomes. This is a world where computers thrive. For example, computers can comb through the massive data companies collect about their customers and illustrate useful patterns. Cinematch, Netflix’s program that matches viewers and DVDs, is a great example. Cinematch is obviously going to be a heck of a lot more accurate than an expert in providing good recommendations.
连续谱的另一端是那些结果范围很大、呈概率分布的问题。在这种情况下——只要满足特定条件——群体的预测比专家更准确。预测市场就是一个绝佳的例子。这些市场的预测始终比最有学识的专家还要精准。
The other end of the continuum has problems that are probabilistic with large ranges of outcomes. Here, crowds forecast better than experts—when certain conditions are in place. Prediction markets are a great example. These markets consistently predict better than even the most learned experts.
我讲一个书里没写的故事。为了确定这本书的书名,我用亚马逊的“土耳其机器人”平台办了一场“书名锦标赛”。这事特别酷。我们让一大群随机用户选出他们最喜欢的书名,并为每份回答支付了极小额的费用。很快,我们就得到了关于候选书名反响的明确反馈。按我喜欢说的那句话,知道一大群随机的人为了 10 美分就愿意回答的问题,最终决定了我这本书的书名——这种感觉真好。但这是千真万确的事!
I’ll mention one story that’s not in the book. In order to determine the book’s title, I hosted a “title tournament” using Amazon.com’s Mechanical Turk. It was totally cool. We actually asked a large random group which title or titles they liked best, offering a micro payment for their answers. In a short time, we got clear feedback on the perception of the contending titles. As I like to say, it’s a great feeling knowing that a large number of random people willing to answer a question for $0.10 determined the title of my book. But it’s the truth!
最后一点:人类确实更愿意听从专家的意见。我们在生活的方方面面都寻找专家,来帮我们做决策。在某些领域,专家确实很棒,极具价值。但对于大量问题,包括与市场相关的大部分问题,专家的表现却很糟糕。
A final thought is that humans really do prefer to defer to an expert. We’re looking for experts in all facets of our lives to help guide our decisions. In some realms experts are great and super valuable. But for lots of problems, including most of those associated with markets, the record of experts is dismal.
《再思考》中对复杂性科学与(观点)多样性崩溃的讨论颇为精彩。复杂性理论告诉我们,在华尔街这样的地方或全球资本市场中,观点多样性有何重要意义?
There’s a nice discussion in Think Twice about the science of complexity and diversity (of opinion) breakdowns. What does complexity theory tell us about the importance of diversity of opinion in a place like Wall Street or in global capital markets?
MM你可以从三个层面来描述复杂适应系统。首先,有一群异质性的、或者说多样化的行动主体——他们可以是市场中的投资者、你大脑里的神经元,或者蚁群中的蚂蚁。其次,你必须让这些行动主体相互互动。最后,涌现出来的就是一个全局系统——股票市场、意识、蚁群。重要的是要强调,整体大于部分之和。这意味着还原论行不通——你无法通过研究部分来理解系统。
MMYou can describe complex adaptive systems at three levels. First, you have a group of heterogeneous, or diverse, agents. These could be investors in a market, neurons in your brain, or ants in an ant colony. Second, you have to let these agents interact with one another. And finally, what emerges is a global system—the stock market, consciousness, the ant colony. It’s important to stress that the whole is greater than the sum of the parts. This means that reductionism doesn’t work. You can’t understand the system by studying the parts.
就像蚂蚁无法告诉你蚁群层面发生了什么一样,你完全可以相信,任何一个单个投资者对市场的运作方式都只有非常有限的理解。
Just as the ants can’t tell you what’s going on at the colony level, you can be pretty sure that any individual investor has a very limited grasp of the market’s workings.
然而,要让这些系统有效运作,你就需要底层行动者的多样性。
For each of these systems to operate effectively, though, you need to have diversity of the underlying agents.
顺便说一句,所有这些系统都会周期性地出现故障。有时故障源于外部冲击,但更多时候,故障源于系统内部的运作机制。它们是内生的故障。在市场上,有繁荣与崩盘;在大脑中,有癫痫——神经元同步放电;在蚂蚁群中,有死亡旋涡——蚂蚁们相互跟随绕圈,直到死去。所有这些故障都有一个共同的根源:多样性的崩溃。不是各个主体独立运作,而是它们的行为被协调同步了。毫不奇怪,我们在自然界中很少看到这类崩溃,很大程度上是因为进化已经找到了确保多样性的方法。但在特定条件下,所有这些系统中都会出现多样性的崩溃。
By the way, all of these systems have periodic failures. Sometimes the failure is the result of an external shock. But more often the failures are the result of the internal workings of the system. They are endogenous failures. In markets there are booms and crashes, in brains it is epilepsy—synchronized firing of neurons— and in ant colonies it’s circular mills, when the ants follow each other around in a circle until they die. And all of these failures have a common root: a breakdown in diversity. Rather than the agents operating independently, their behavior is coordinated. Not surprisingly, we rarely see these types of breakdowns in nature, in large part because evolution has found ways to ensure diversity. But under certain conditions you see diversity breakdowns in all of these systems.
现在不难看出这如何适用于华尔街。当观点多元化且得到恰当汇总时,市场会相当有效。但一旦多元化瓦解,人们开始相互模仿,市场就会出现无效率。挑战在于:恰恰在无效率最严重的时候,你最强烈地想要随大流。从定义上说,事实就是如此。
It’s now pretty easy to see how that would apply to Wall Street. When views are diverse and properly aggregated, you’re going to get pretty efficient markets. But when diversity breaks down and people start to imitate one another, you will get inefficiency. The challenge is that you will feel the strongest inclination to go with the crowd precisely when the inefficiencies are greatest. This is by definition true.
机构强制力(institutional imperative)是沃伦·巴菲特用来解释组织盲目模仿同行趋势的术语。高管们该如何警惕机构强制力?
The institutional imperative is Warren Buffett’s phrase to explain the tendency of organizations to mindlessly intimate what peers are doing. How can executives watch out for the institutional imperative?
MM防范盲目模仿的最佳方法之一是不断问一个天真的问题:我们为什么要这样做?比如,我们为什么要这样支付薪酬?我们为什么要从事这个行业?我们为什么要提供盈利指引?我们为什么要提议这笔并购交易?问天真的问题是彼得·德鲁克的一个诀窍,如果你足够频繁地问并诚实回答,这就会引领出好的思考。
MMOne of the best ways to guard against mindless imitation is to constantly ask the naïve question: Why are we doing this? So, for example, why are we paying people this way? Why are we in this business? Why are we providing earnings guidance? Why are we proposing the M&A deal? Asking the naïve question was one of Peter Drucker’s tricks, and if you do it frequently enough and answer honestly, it’ll lead to good thinking.
好的决策都源于对“为什么”这个问题的扎实回答。巴菲特讲过一个精彩的故事:一位高管试图说服董事会收购另一家公司。在没能让董事会相信这笔交易的价值后,他基本上就是一句:“哎呀,各位,别人家的孩子都这么干。” 每当你听到这样的回答,就得当心了。
Good decisions come with sound answers to the “why” question. Buffett tells a great story about an executive trying to make his case for acquiring another company. After failing to convince the board of directors of the deal’s virtue, he basically says, “aw, c’mon folks, all the other kids are doing it.” Whenever you get an answer like that, look out.
蚁群和蜂巢的运作方式,能告诉我们关于华尔街以及商界有效决策的什么道理?
What do ant colonies and bee hives tell us about effective decision making on Wall Street and in the business world?
MM我对社会性昆虫如何解决难题感到着迷。它们在没有领导者、个体智慧有限的情况下,处理复杂任务。但结果却令人惊叹。
MMI am fascinated by how social insects solve difficult problems. They deal with complex tasks with no one in charge and with limited individual smarts. Yet the results are simply amazing.
对我来说,两个重要的启示来自集体的力量与多样性。人类天生倾向于听从专家的决定,而社会性昆虫却证明——对它们而言事关生死的难题——蜂群能够成功应对。这个想法与人类的思维模式截然相反。我一次又一次听到高管们对股市或预测市场表示疑虑。人们就是对集体决策这个概念感到不自在。
The two big lessons for me are about the power of collectives and diversity. While humans naturally want to defer to an expert to make a decision, social insects demonstrate that hard problems—for them, matters of life and death—can be successfully handled by the hive. This is an idea that runs very counter to how humans think. Time and time again, I have heard executives express misgivings about the stock market or prediction markets. People just don’t feel comfortable with the notion of collective decision making.
第二个教训我们之前已经讨论过——多样性。许多组织会告诉你们他们致力于多样性,但他们往往关注的是社会身份多样性——性别、种族、年龄、宗教等。但真正重要的是认知多样性。这在组织和市场中都是如此。
The second lesson is something we’ve already discussed—diversity. Many organizations will tell you they are committed to diversity, but often what they’re committed to is social identity diversity—gender, race, age, religion, etc. But what really matters is cognitive diversity. That’s true in organizations and in markets.
你在书中花了不少篇幅讨论均值回归。你指出,人们在均值回归方面会犯三种错误。请详细说明。
You spend time discussing mean reversion in the book. You note that when it comes to reversion to the mean, they make three kinds of mistakes. Please elaborate.
MM第一个错误就是完全忽视均值回归。在我之前举的那个例子中,养老金计划发起人聘用业绩出众的经理人、解雇业绩不佳的经理人,这正是当下的现实。另一个故事浮现在我脑海中。有一次,我向一家公司的高管层讲解均值回归现象。他们心领神会地点头。但随后,首席执行官却坚持认为,尽管他们理解并赞同均值回归的概念,但他们已经找到了规避它的办法。事实证明,他们并没有规避掉——他们后来的财务业绩就是明证。
MMThe first mistake is to ignore it all together. In the example I cited before, about plan sponsors hiring outperforming managers and firing underperforming ones, that’s what’s going on. Another story comes to mind. I was once presenting on reversion to the mean to the senior management of a company. They nodded along knowingly. But then the CEO proceeded to insist that while they understood and agreed with the concept of reversion to the mean, they had figured out how to avoid it. Suffice it to say that they did not avoid it, as their subsequent financial performance attested.
第二个错误是人们误读了均值回归的含义。有些人认为它意味着结果会趋向于平均水平移动,但这并不是实际发生的。准确的说法是:如果近期结果受益于大量技巧和大量运气,那么下一次结果很可能会更接近平均值,因为好运气难以持续。但同理,一个平均结果之后也可能出现好得多或差得多的结果——如果好运或霉运发挥作用的话,这就是均值排斥。核心思想在于:即使分布形态随时间保持不变——比如企业投入资本回报率的分布——运气也会重新洗牌各公司的排位。并不存在趋向平庸的力量,只是不断从运气箱里抽签而已。
The second mistake is to misinterpret what reversion to the mean says. People sometimes believe it means that results tend to migrate toward average. But that’s not really what’s going on. It is accurate to say that if a recent outcome benefitted from lots of skill and lots of luck, the next outcome will likely be closer to the average as the good luck is unlikely to persist. But by the same token, an outcome that was average may be followed by an outcome that’s much better or worse if good or bad luck comes into play, which is repulsion from the mean. The big idea is that even if the distribution stays the same over time—say, for corporate returns on invested capital—luck will reshuffle the positions of the companies. There is no tendency toward mediocrity, just draws from the bin of luck.
最后一个错误,是倾向于把回馈与均值回归混为一谈。打个比方,如果你女儿数学考试拿了个相当出色的成绩——这里面很可能既有实力的成分,也有运气的成分——你可能会表扬她功课做得好。然后你多半会发现,她下一次考试成绩就没那么好了,因为她的好运气未必能延续。于是你可能会觉得,问题出在你的表扬上,但实际上,她的表现不过是均值回归的体现。
The final mistake is the tendency to confuse feedback with mean reversion. For example, if your daughter comes home with a really great grade on her math test, which is likely to be part skill and part luck, you might praise her for her good work. You’ll then likely see her next test score be not quite as good, as her good luck may not continue. So you might think that your praise was the problem, when in fact her performance simply reflected mean reversion.
当然,批评也是一样。假设你女儿数学考试考砸了,你狠狠训了她一顿。她下次考试时,也许碰巧运气好,成绩提高了。于是你可能会错误地认为,是你的批评起了作用。
Of course, the same is true of criticism. Pretend your daughter comes home with a very poor grade on her math test and you read her the riot act. She’ll likely do better on the next one as the result of better luck. So you might falsely conclude that your criticism helped her.
理解均值回归带来的最大教训和机遇是什么?
What is the greatest lesson and opportunity from understanding reversion to the mean?
MM我的一大心得是,反馈应该只聚焦于个人能够掌控的那部分表现。这话说起来很容易,做起来却相当难。举个例子,在评估一位同事的表现时,你必须尽力把分析重点放在过程上。
MMOne big insight for me is that you should focus feedback only on the part of performance that is under the individual’s control. That’s very easy to say, but really hard to do. For example, when evaluating the performance of an associate, you must do your best to focus the analysis on the process.
机会就在于别人看不见的地方。如果你看到极端的表现——无论是好是坏——要认识到这种表现不太可能持续。这方面有一整套研究。
The opportunity lies in seeing it where others don’t. If you witness performance that is at the extremes— either good or bad—recognize that such performance is unlikely to persist. There’s a whole strand of research
有一项对媒体的研究显示,当一家公司备受赞誉时,它最好的时光很可能已经过去了;而当一家公司被严厉批评、被认为毫无前途时,更美好的日子往往就在前方。
that studies the media and shows that when a company is celebrated the best times are likely behind it, and when a company is taken to task as being no good better days often lay ahead.
推特二把手最近坦言,自己还真不知道怎么给这家公司定性,尽管它眼下红得发紫。在我看来,他这是打起了退堂鼓。听起来,他也信奉丹尼尔·卡尼曼那套关于 21 世纪成功与巨大成功的公式。你同意吗?
Twitter’s second in command frankly admitted recently that he really didn’t know how to describe the company yet, despite being all the rage today. It sounds to me like he is thinking twice. It also sounds like he subscribes to Daniel Kahneman’s formula for success and great success in the 21st century. Do you agree?
MM我没见过那段话,所以无法直接评论。但我要说的是,一家吸引用户成功却尚未完善商业模式的公司,可能很难描述清楚。谷歌早期也是这种情况。
MMI didn’t see that quote so can’t comment on it directly. But I will say that it may be difficult to describe a company that has had success in attracting users without yet having fleshed out a business model. This was true of Google in the early days, too.
我还要提醒大家,注意别像纳西姆·塔勒布说的那样,“被随机性愚弄”。很多时候,人们把自己的成功归因于聪明,而真相不过是运气好。正如卡尼曼所指出的,巨大的成功是出色的能力加上大量的运气。承认这两点,非常重要。
I’d also say it’s good to be mindful not to get “fooled by randomness,” as Nassim Taleb would say. Too often, people attribute their successes to smarts, when the truth is they were just lucky. As Kahneman noted, great success combines good skill with a lot of luck. It’s important to acknowledge both.
我长期以来一直对“光环效应”(Halo effect)——人类倾向于根据总体印象做出具体推断的习性——着迷,很高兴看到你在书中讨论了这一点。作为美盛资本管理公司的首席投资策略师,你大量走访公司高管。当你和他们讨论光环效应时,他们的反应如何?
I’ve long been fascinated by the Halo effect – the human proclivity to make specific inferences based on general impressions - and was glad to see you discuss it in your book. You do a lot of meeting with company executives in your position as Chief Investment Strategist at Legg Mason Capital Management. What’s the reaction of executives when you discuss the Halo effect?
MM他们完全不知道我在说什么!
MMThey have no idea what I’m talking about!
说真的,高管们要学到的核心一课是:你千万要小心从成功故事里提炼教训。正如我们之前谈过的,很多事情之所以成功或失败,很大程度上取决于环境。问题在于人们就爱听故事。那些最畅销的商业指南书的共同点,就是它们都讲了精彩的故事。至于研究有没有漏洞,谁在乎呢。故事才是王道。
Seriously, the main lesson for executives is that you have to be careful about drawing lessons from success stories. As we discussed before, a lot of what makes for success or failure is based on circumstances. The problem is people want stories. The common denominator of the best-selling business how-to books is that they tell great stories. Never mind that the research is flawed. The stories carry the day.
你提到人们做每件事情之前不应该三思。那么什么时候最适合三思?
You mention that people shouldn’t think twice before every decision. When are the best times to think twice?
MM是的,实际情况是,你的大多数决策要么有明确答案,要么无关紧要。当然,遇到这些情况你根本不用多费脑筋。
MMYeah, the fact is that most of your decisions will either have a clear answer or will not be consequential. Of course, you won’t need to think twice in those instances.
但在某些情况下,你的大脑会倾向于用一种并非最优的方式去处理问题。我建议分三步走。第一步是做好准备——说白了就是了解这些情况。我在书中描述了八种这样的情形。所以去阅读它们、学习它们,建立起你的心理数据库。
But there are certain situations when your mind will want to approach the problem in a way that’s suboptimal. I recommend three steps. The first is to prepare—basically to learn about these situations. I describe eight of them in the book. So read about them, learn about them, and build your mental database.
第二点是识别能力。这类局面会以各种伪装出现在不同领域里。一旦你掌握了它们,你就会在职业生涯、个人生活,甚至是在电视上看球赛时发现它们的身影。等你把这些局面吃透之后,你就会发现它们无处不在。
Second is recognition. These situations will show up in various guises in different fields. Once you learn about these situations, you’ll see them in your professional life, your personal life, and even while watching a ballgame on TV. Once you’ve got these situations down, you’ll see them everywhere.
最后,我提供应对这些情况的方法。每一章都给出了如何减少或管理这些错误的具体思路。
Finally, I offer ways to deal with these situations. Each chapter offers some specific ideas on how to mitigate, or manage, the mistakes.
我想强调一点。《三思而后行》这本书讲的核心其实是机会。市面上很多讲决策的书满足于指出一个事实:人们在决策时远非理性。这固然没错,但看完之后并不会让你感觉太好。
I want to emphasize one point. Think Twice is really about opportunity. A lot of decision making books are satisfied to point out that people are far from rational in their decision making. This, of course, is true. But it doesn’t leave you feeling very good.
《三思而后行》反其道而行之,建议你去思考这些错误中的正面机会。这种机会有两种形式。第一种当然是减少自己的错误,这就像网球比赛中非受迫性失误更少的选手——失误越少,成绩越好。第二种,你可以利用他人因这类错误而造成的市场定价偏差来获利。
Think Twice turns this on its head and suggests that you consider the upside in these mistakes. The opportunity comes in two flavors. First is, of course, reducing your own mistakes. This is like the tennis player who makes less unforced errors. Fewer mistakes equal better outcomes. Second, you can take
当别人犯下这些错误时,我们能从中获益。正因为这些错误如此普遍且难以驾驭,它们本身就会带来机会。
advantage of these mistakes when other people make them. Precisely because these mistakes are so prevalent and difficult to manage, they will present opportunity.
在最后一章里,你谈到了人们可以采取哪些措施来改善自己的决策能力。那你认为,其中两三个最重要的因素是什么?
In the final chapter you talk about things people can do to improve their decision making. What are two or three most important things in your opinion?
MM起点是去了解那些错误。那确实很有价值,也很有帮助。下一步是坚持写决策日志。当你做一个有重大影响的决定时,写下你是怎么决定的、你是如何得出这个决定的、以及你预期会发生什么。如果你愿意的话,还可以记下你当时的情感和身体感受。决策日志会给你提供一个审视自己决策的机会,本质上就是给自己反馈。周围最强大的认知偏差之一就是事后聪明偏差。一旦我们知道发生了什么,就会莫名觉得自己早该料到。后视镜让我们对过去看得清清楚楚。但把自己的决定白纸黑字写下来,就能抵消这种偏差。
MMThe starting point is to learn about the mistakes. That’s really valuable and helpful. Next is to keep a decision-making journal. When you make a decision of consequence, write down what you decided, how you came to that decision, and what you expect to happen. If you’re so inclined, note how you feel emotionally and physically. The decision journal will present an opportunity to audit your decisions, effectively giving yourself feedback. One of the most powerful biases around is hindsight bias. Once we know what happened, we somehow think we saw it coming. Our rearview mirror provides 20/20 vision into the past. But having your decisions written in your hand will offset that bias.
我还建议你设身处地为他人着想。这在评估动机时会很有帮助。是什么激励人们去做他们做的事?与其去评判,不如试着去理解。而当你理解了是什么让人行动起来,你就更有能力去预测和欣赏他们如何做决定。
I’d also recommend putting yourself in the shoes of others. One area where this is helpful is in assessing incentives. What motivates people to do what they do? Try not to judge so much as to understand. And when you understand what makes people tick, you’re in a much better position to anticipate and appreciate how they decide.
关于这本书我们能聊的还有很多,但你已非常慷慨地给了我们时间,对此我们深表感谢。再次感谢你与我们分享想法。祝你的新书一切顺利,期待你未来的作品。
There is so much more about the book we could discuss, but you’ve been gracious with your time and we appreciate it. Thanks again for sharing your thoughts with us. We wish you all the best with the new book and look forward to your future efforts.
MM谢谢你,史蒂夫。这是我的荣幸。
MMThank you, Steve. The pleasure was mine.
关于迈克尔·莫布森:
About Michael Mauboussin:
迈克尔·莫布森是 美盛资本管理公司 的首席投资策略师,也是 哥伦比亚商学院 金融学兼职教授。他是广受赞誉的《超越你所知》一书的作者,也是《预期投资》的合著者。如需了解迈克尔的更多信息,请访问:
Michael Mauboussin is Chief Investment Strategist at Legg Mason Capital Management and adjunct professor of finance at Columbia Business School. He is the author of the acclaimed book More Than You Know, and coauthor of Expectations Investing. For more information about Michael, please visit:
http://www.michaelmauboussin.com/
http://www.michaelmauboussin.com/
克里斯·塔特尔,研究总监 斯蒂芬·韦特,战略总监 罗伯特·麦克赫菲,机构销售 杰奎琳·瓦蒂莫,业务经理 本·斯坦,助理分析师
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