译注：先解释一下后文中不断提到的定量研究（quantitative research）和定性研究（qualitative research），这里两者都是指做产品的市场/用户研究，其中：

定量研究（quantitative research），一般指会产生统计报告（各种数字）的调查，比如对产品感兴趣人的百分比，使用过竞争对手产品人的百分比，对产品的评分什么的。定量研究的手段有用户问卷调查，或是小组座谈会（focus group）等。

定性研究（qualitative research），一般不会产生数字报表，它有可能是产品经理和客户一对一的面谈，用来发现一些用户面对的问题或是潜藏的需求。这样的研究由于耗时大，所以不可能大规模开展。
本文英文原标题即为“理解定量研究与定性研究”，译者担心略显枯燥，于是标题党的改换成现在的样子。

如果你想做一个坏的产品经理，只做定量研究就可以了。做生意就是和各种各样的数字打交道，要不然，为什么学校一定要给你开一门统计学呢？如果你搞不出什么看上去像是统计报表的东东来支持你的看法，你的看法多半不靠谱。想想看，一个上百万用户的产品，怎么能依靠几十个人的意见来做呢。问题不在于用户有什么看法，而在于总共多少用户有这种看法。

如果你想做一个好的产品经理，你得定量研究和定性研究两手抓（两手都要...)。数字是好东东，但是只看数字会让你遗漏关键的信息。

在产品开发过程中， 通过定性研究得到的发现可以（或者说应该）通过定量研究来证明。比如说，你可能通过用户访问或是种族研究（译注：这个比较西方，中国没什么种族的问题）发现了一些潜藏的用户需求。所以，你接着搞了一次较大规模的问卷调查，希望从更多的用户那里了解这个需求是不是真的重要，以及用户愿意花多少钱为解决问题买单。

很多才入行的产品经理几乎没有任何市场研究的经验。一旦有市场研究的需要，他们往往就那么两招：问卷调查和小组座谈会（focus group）。产品经理们甚至可能没有意识到还有其它的方法做市场研究，也不理解这些方法之间的区别。

一语以概之：

定性研究关注于发现需求，理解用户，探索未知（不仅你不知，你的用户也未必意识到了）。
定量研究关注于验证和细化定性研究的发现。

再说详细一点，如果你希望探索那些用户自己都不能明确表达的需求，递给他一张问卷让他打出1到10分对你没什么帮助。当然，这种卷子可以帮助你决定产品功能的优先级。

同样的，当你想出一个新点子，希望看看人们是否愿意为了这个产品买单，你搞个6个人的小组座谈会也没有意义。但是这个座谈会可以帮助你理解潜藏的问题，用户偏好以及一些细节。

产品经理没必要成为定量研究和定性研究的专家，但是有一些经验总是好的。重要是你得理解这些市场研究手段的用途和局限。

有很多不错的定量研究和定性研究的书。下面推荐两本：

Observing the User Experience: A Practitioner’s Guide to User Research（关注用户体验，用户研究实践者指南，Mike Kuniavsky著）。这本极其优秀的书介绍了大量的用户调查手段，特别关注在互联网，软件和高科技产品上。它非常详细的描述了种种技巧指导你学习，同时又不失参考手册一般的简洁。
Qualitative Market Research: A Comprehensive Guide （定性市场研究完全指南，Hy Mariampolski著）. 这本书针对各种定性市场研究方法提供了不错的概述以及实施指南。
好的产品经理应该善用这些资源来理解不同的市场研究和用户研究手段，并且在工作中合理使用。

If you want to be a bad product manager, rely solely on quantitative research. Business is about numbers, after all, and there’s a reason you had to learn statistics in school. If you can’t prove something to a level of statistical significance, it must not be reliable. You would never make a decision about a product that’s used by millions of people by just getting input from a few dozen. What people say is not nearly as important as how many people say it.

If you want to be a good product manager, utilize both quantitative and qualitative research for decision making. Numbers are good, though on their own they can not tell the whole story.

Quantitative research is especially useful in product development as a way of confirming findings through qualitative research. For example, you may conduct customer visits or ethnographic research and uncover some unmet needs. You may want to conduct a survey of a wider group of customers to confirm your findings and get more input on specific aspects, such as how important this need is and the cost to the customer of not being able to currently solve this problem.

Many inexperienced product managers have little if any background in any sort of market research techniques. They may rely on the standard techniques — usually surveys and focus groups — whenever research needs to be conducted. Product managers may not even realize that there are other methods available or may not understand why you would use one method over another.

To generalize, qualitative research is usually better for exploring, understanding, and uncovering, while quantitative research is generally better for confirming and clarifying.

If you are trying to discover unmet needs that consumers can not articulate, there is no way that a survey asking respondents to rank items from 1-10 will offer any insight. However, that method would make sense if you have a good idea about priorities for features and you want to get confirmation from a large sample set.

Similarly, if you want to determine whether a market exists for a new product idea and whether consumers would be willing to pay for the product, a single focus group with 6 participants will not provide the information you need. Instead, that would be a useful approach to take if you are trying to understand underlying issues, preferences, and factors that could be helpful in defining a potential solution.

Product managers do not necessarily need to be experts in conducting qualitative and quantitative research, though some experience is certainly useful. More important, however, is that product managers understand the fundamentals of both types of research, their applications and their limitations.

There are many great resources on qualitative research methods; here are two which are recommended:

Observing the User Experience: A Practitioner’s Guide to User Research by Mike Kuniavsky. This is a fantastic guide to a huge variety of different user research techniques, especially useful for web, software, and technology products. It is sufficiently detailed to be used as a learning guide, while written succinctly enough to be useful for quick reference. (In the interest of fairness, I will note that this book is published by a division of Morgan Kaufmann, which is an imprint of my former employer, Elsevier. However, I have no specific organizational or financial connection to this book. I would gladly recommend it even if it was the product of another publisher or if I was not formerly employed by Elsevier.)
Qualitative Market Research: A Comprehensive Guide by Hy Mariampolski. This provides an excellent overview of different methods along with guidance for those actually conducting the research.
Good product managers will use these and other resources to understand more about the different types of market and user research so that they can utilize the right techniques for the right situation.