Strong Opinions, Weakly Held — a framework for thinking

As product managers, entrepreneurs, and leaders, we are often confronted with the challenge of making decisions under uncertainty. This is especially true in situations where we are trying to decide something based on the external environment — market growth trends, customer needs, or competitor reactions. To be an effective leader, however, it’s very important to be able to make the right decisions in a timely manner, despite the uncertainty.

To help us reach the correct decision, we can use a framework called “Strong Opinions, Weakly Held,” developed by technology forecaster and Stanford University professor Paul Saffo.

The Strong Opinions, Weakly Held process

This framework enables us to make decisions or forecasts with incomplete information. For example, you may have to forecast the revenue potential of a new business opportunity, or the impact of a new product. Despite the lack of available information, you should develop a tentative hypothesis for what the decision or forecast should be. Then actively gather information that either supports or refutes the hypothesis. The important part is that if you uncover information that refutes the hypothesis, then change your hypothesis. Don’t cling to your original idea, decision, or forecast even in the face of contradictory information. In fact, actively seek the contradictory information — this provides you with data to iteratively improve the forecast, until you get to the right answer.

Saffo describes his process as follows:

“I have found that the fastest way to an effective forecast is often through a sequence of lousy forecasts. Instead of withholding judgment until an exhaustive search for data is complete, I will force myself to make a tentative forecast based on the information available, and then systematically tear it apart, using the insights gained to guide my search for further indicators and information. Iterate the process a few times, and it is surprising how quickly one can get to a useful forecast.”

This is Saffo’s process for “Strong Opinions, Weakly Held.”

“Allow your intuition to guide you to a conclusion, no matter how imperfect — this is the ‘strong opinion’ part. Then –and this is the ‘weakly held’ part– prove yourself wrong. Engage in creative doubt. Look for information that doesn’t fit, or indicators that pointing in an entirely different direction. Eventually your intuition will kick in and a new hypothesis will emerge out of the rubble, ready to be ruthlessly torn apart once again. You will be surprised by how quickly the sequence of faulty forecasts will deliver you to a useful result.”

So the first step in this process is to form a “strong opinion” relatively quickly. How do you do that? You need a toolkit of problem-solving frameworks, combined with the intuition that often comes from pattern-matching and experience.

Common problem-solving toolkits include deductive, inductive, or abductive reasoning; developing a decision tree or issue tree; or performing root cause analysis and asking “five why’s”. You then use your intuition to tune your hypothesis, based on your pattern-matching skills. If you are facing a new domain that you have not encountered, you could consult with a couple of experts in the field — their experience and wisdom can compensate for your lack of familiarity.

The point here is to develop a “strong opinion” quickly — this need not be the correct answer, but your best guess based on your problem-solving skills and pattern-matching experience.

Now comes the “weakly held” part. You want to actively prove yourself wrong by seeking disconfirming evidence. Surround yourself with people who will dare to disagree with you, who will surface this disconfirming evidence and challenge your thinking. This will enable you to pressure test your thinking and continue iterating your hypothesis. The important thing here is you must not cling to your strong opinion too strongly. Otherwise, you won’t be able to swap out your hypothesis for a better one as you gather new disconfirming evidence. So you have to be willing to change your mind — and your hypothesis — as you encounter disconfirming evidence. Your strong opinions have to be weakly held.

McKinsey’s Day One Hypothesis

I didn’t know it at the time, but I was taught to use a version of Strong Opinions, Weakly Held when I was a strategy consultant with McKinsey. While there, I learned of a technique called the “Day One Hypothesis.”

At the beginning of any new McKinsey client engagement, we were expected to develop a “Day One Hypothesis.” Based on the high-level facts that we had learned within the first 24 hours of the project, we were forced to develop an early hypothesis of what the solution to the client’s problem was.

As mentioned above, how you develop your hypothesis is a combination of good problem solving skills, pattern matching, and intuition. At McKinsey, we often used issue trees to break down complex business problems. We were also often encouraged to “get smart” about a particular area by reading 3rd-party analyst research, or interviewing industry experts. But the expectation was that within your first day on the project, you should come up with your early hypothesis about the right decision to make. Then, you can always gather additional data to refine your hypothesis over time. You should be open to changing your hypothesis as you gather additional data, but you should start out with a hypothesis on Day One. This approach sounds a lot like Strong Opinions, Weakly Held — but under a different name.

Why is Strong Opinions, Weakly Held effective?

There are three reasons why the Strong Opinions, Weakly Held approach is an effective way to make decisions under uncertainty:

  1. Leverage your team’s collective wisdom
  2. Overcome your biases
  3. Have an on-demand decision

Leverage your team’s collective wisdom

Your process of getting to an answer will inevitably involve sharing your “strong opinion” with people on your team, and encouraging them to dissent and share disconfirming evidence as part of the “weakly held” process. In doing so, you will elicit feedback from your teammates in the form of additional ideas, intuitions, and perspectives. This is incredibly valuable, because you can now leverage their past experiences and pattern-matching skills, the information and context they have that you may have missed, and the creativity that they bring to the table. Your answer or decision will only improve from getting exposure to this additional information and experience.

Particularly if you seek disconfirming evidence from them, you will be able to strengthen your answer or decision by continuing to pressure test it and iterate it. In order to stimulate this type of debate where your teammates are challenging you, however, you need to encourage them to “dare to disagree.” You must have a willingness to change your mind; encourage diversity within your team; and create the psychological safety for people to speak up.

Overcome your biases

We all have inherent biases due to our way of thinking. Here is just a small sample of common cognitive biases:

  • Law of small numbers: We bias towards anecdotal examples rather than statistically significant data. So we may generalize one incident to an entire population.
  • Confirmation bias: We may be too quick to seize on limited evidence that confirms our existing perspective. And we may be too quick to dismiss contradictory evidence for the same reason.
  • Over-optimism: We tend to come up with plans and forecasts that are unrealistically close to best-case scenarios.
  • Assigning cause to random chance: We are quick to assign causality to events that may in fact be unconnected.
  • Recency bias: We bias towards recent events when we make judgments and decisions.

This list goes on and on. The “weakly held” part of Strong Opinions, Weakly Held enables you to overcome these biases. Your initial “strong opinion” may be based on some of the above cognitive biases. That’s perfectly ok, as long as you engage in the “weakly held” part of the process. By seeking the disconfirming evidence, you are actively working against confirmation bias first and foremost. But you are also likely to discover information and perspectives that may help you overcome any of the other biases as well (law of small numbers, over-optimism, recency bias, etc.).

Have an on-demand decision

One other reason why this approach is helpful is that after you form your “strong opinion,” you always have a working decision that you can fall back on at any point in time. You may try to gather additional data as part of “weakly held,” but based on the data that you have already reviewed at that point in time, your current hypothesis is your current decision. In other words, you have an “on-demand” decision ready whenever you are forced into making it. This decision is your current thinking based on the Strong Opinions, Weakly held approach.

This approach works best in two situations — when you need to time box your decision-making process, or when you are unsure of when you will be called upon to make the decision. In either case, when you reach your deadline, you go with your current hypothesis as the current decision. And until you reach the deadline, you continue to gather disconfirming evidence and tear apart your “strong opinion” to continue iterating and strengthening your hypothesis.


Strong Opinions, Weakly Held is a phenomenal process for reaching the best decision or forecast when faced with complexity, uncertainty, and time pressure. I have personally used this approach many times during my career as a McKinsey strategy consultant, entrepreneur, and product leader at Twitter.

Force yourself to create an initial hypothesis (“strong opinion”) quickly based on your problem-solving skills, intuition, and pattern-matching experience. Then tear the hypothesis apart by seeking disconfirming evidence and challenging your own thinking (“weakly held”). The reasons why “strong opinions, weakly held” is so effective is because it

  • Leverages your team’s collective wisdom
  • Overcomes your own biases
  • Enables you to have an on-demand decision

For the process to work well, you need to surround yourself with people who will dare to disagree and challenge your thinking. This requires you to be willing to change your mind, to surround yourself with diverse perspectives, and to create the psychological safety for people to speak up.

If you follow the “strong opinions, weakly held” process, you will not only get to a better answer or decision. You will also develop a stronger conviction in that answer or decision, because you have thoroughly “pressure tested” your thinking against disconfirming evidence. Your ultimate answer will have withstood the challenge of multiple rounds of having holes poked in it. You will be much more confident in vigorously advocating for your decision after having gone through this process.

So the next time you are faced with a complex decision with a lot of unknowns, be sure to follow the “strong opinions, weakly held” approach. This process will not only get you closer to the truth, but also strengthen your confidence in your eventual answer.

With that, let me leave you with a quote from Nobel Prize-winning physicist Richard Feynman about the “weakly held” part of Strong Opinions, Weakly Held: