In the book, Clear Thinking, Shane Parrish offers up essential mental methods for clear decision making – tools that help us pause, focus, and act wisely when it matters most. Parrish shows that poor choices rarely stem from a lack of intelligence. Instead, they often arise when we fail to slow down and think clearly under pressure. When stress, ego, or emotion clouds our judgment, we default to shortcuts that feel safe but lead to poor outcomes.
Parrish’s six-step framework isn’t theoretical – it’s practical. It helps you define what truly matters, explore options with clarity, and act with precision. More than a model, it’s a repeatable method for clear thinking.
1. Define the Problem
Clear decision making begins with problem clarity. And as Shane Parrish writes, the responsibility to define the problem lies squarely with the decision-maker — not the group; nor the loudest voice in the room. The person accountable for the outcome must sort fact from opinion and get to the truth of what’s happening. That process starts by identifying two things. Parrish writes:
Defining the problem starts with identifying two things: (1) what you want to achieve, and (2) what obstacles stand in the way of getting it. Unfortunately, people too often end up solving the wrong problem.
Groups tend to leap toward solutions without questioning the problem itself. That’s the “social default” in action – where the need to act overtakes the need to think. Parrish warns that we’re trained to solve problems, not define them. Great decision-makers slow things down, ask deeper questions, and gather a broader view. “Since you can’t solve a problem you don’t understand,” he writes, “defining the problem is a chance to take in lots of relevant information.”
2. Explore Possible Solutions
Once the problem is clear, don’t just fix what’s broken – explore what’s truly possible. Parrish urges us to image different futures, not just desirable ones. Avoid magical thinking. Problems don’t disappear – they evolve if ignored. Use mental rehearsal to expose the worst-case scenarios, such a “premortem” analysis. Premortem is based on an ancient Stoic mental or virtue model: Premeditatio malorum. As Parrish writes:
“[T]here’s a way to convert the hindsight of tomorrow into the foresight of today. It’s a tough experiment that psychologist call premortem. The concept inst new, it originates in Stoic philosophy. Seneca used premeditatio malorum (“the premeditation of evils”) to prepare for the inevitable ups and downs of life. The point isn’t to worry about problems; it’s to fortify and prepare for them.”
This mindset is vital. If the pitch fails, the deal falls apart, or your launch flops – what’s next? “The best decision-makers know that bad things happen, and that they’re not immune. They don’t just wing it and react. They anticipate and make contingency plans,” Parrish writes.
This is where second-level thinking comes in. Parrish calls it the antidote to impulsive action. Ask yourself, “And then what?” That answer separates the quick fix with the wise move. Binary choices – yes or no, stay or quit – often reflect shallow thinking. Instead, force a third options. Look for “both-and” combinations. Parrish highlights a few pointers necessary to safeguard the “solution-exploring stage.” He writes in his book:
- The 3+ Principle:Force yourself to explore at least three possible solutions to a problem. If you find yourself considering only two options, force yourself to find at least one more.
AND then, the two safeguards against binary thinking: - Safeguard #1: Imagine that one of the options is off the table. Take each of the options you’re considering, and one at a time, ask yourself, “What would I do if that were not possible?”
- Safeguard #2: Come up with Both-And options. Try to find ways of combining the binary. Think not in terms of choosing either X or Y, but rather having both X and Y.
Ask yourself: Could you stay in the job and build a side project? Could you decline the offer and negotiate better terms later? The best options emerge when you push beyond the obvious.
3. Evaluate the Options
Once you’ve gathered possible solutions, 
the next step is choosing the best one. Parrish recommends clarity: what matters most in this decision? If you don’t know, you’re not ready to choose. Bad decisions often come from using outdated or irrelevant filters – choosing what’s fast instead of what works.
To make clarity actionable, build your system like a decision tree. Assign weight to each criterion. Then test each option: which is most aligned? Which introduces the fewest unknowns? Which promotes your long-term goal, over a short-term fix? Good filters remove emotional noise and reveal trade-offs. To identify the most important option, Parrish recommends utilizing the sticky-note method. It goes like this:
Use sticky notes to list out your decision criteria – write only one per card. Keep them separate, because soon they’ll have to compete. Start by picking the one that feels most important and place it aside. Then, grab another sticky-note and compare it to the third. Ask yourself, “If I absolutely had to choose between only these two, which matters more?” Repeat the process, even if the remaining two seem compatible. The goal isn’t to eliminate one – it’s to discover which matters more. You don’t need perfect information: You need clear thinking.
But how to do you retain high-fidelity information? As Clear Thinking outlines:
- Run Small Tests to Learn Fast: Treat experiments as low-risk ways to gather real insight. For example, if you’re unsure if people would pay for your product, try selling it before you build it. Testing reveals reality faster than speculation.
- Understand Others’ Incentives: When gather information, consider how others’ goals shape what they share. Try to see situations through their perspective. Even if you disagree, their lens can reveal something useful.
- Ask Better Questions: Don’t ask what someone thinks – ask how they think. Push past surface opinions. Focus on their decision process, not just their conclusion.
- Seek Fresh, Relevant Expertise: Find people with a deep knowledge – either in one field or across many. For tactical advice, talk to someone who has recently solved the exact problem you’re facing.
Furthermore, Parrish argues that decision-making is more than simply seeking information. Instead, it’s about gathering information that is relevant to our decisions. Doing so requires asking the right questions. As Parrish outlines:
Question 1: What are the variables you’d use to make this decision if you were in my shoes? How do those variables relates to one another?
Question 2: What do you know about this problem that I (or other people) don’t? What can you see based on your experience that someone without your experience cant? What do you know that most people miss?
Question 3: What would be your process for deciding if you were in my shoes? How would you go about doing it? (Or: How would you tell your mother/friend to go about doing it?)
4. Do It! (It’s very hard)
You’ve evaluated your options, now it’s time to act. But action doesn’t fail from confusion; It fails from avoidance. Parrish points out that we often know what to do. But it feels uncomfortable, so we wait. We fear difficult conversations, letting people down, or making irreversible mistakes.
Parrish offers a better lens: distinguish decisions as how reversible and consequential they are. If a decision is low-cost and easy to undo, act fast – and adjust later. If the stakes are high and hard to reverse, wait as late as possible. You can gather more information and preserve your option. When failure is cheap, speed matters, When it’s expensive, thoughtfulness does.
Parrish outlines his “Three Principles for Action”:
1. The ASAP Principle: If the stakes are low, decide quickly. Waiting is wasteful.
2. The ALAP Principle: If the stakes are high, wait as long as you can. Buy time. Watch for new data.
3. Stop, FLOP, Know Principle: Stop researching when you 1) stop learning anything new, 2) miss your First Lost OPportunity, or 3) gain insight that makes the answer obvious.
5. Margin of Safety
Clear decision-making isn’t just about making good choices – it’s about protecting yourself when good choices still go wrong. A margin of safety is a buffer between what you expect and what might happen instead. Parrish explains that we often skip this step because we assume the future will look like the past. That assumption leads to fragile decisions, especially in high-stakes environments. As Parrish writes, “It’s much easier to plan for things that could go wrong in advance when you’re calm and open-minded than it is to respond when things are in the midst of going wrong.”
The mistake most people make? They plan for the best-case scenario. But the smartest decision-makers prepare for volatility. Engineers design bridges to hold twice the expected load. Warren Buffett won’t but a stock unless it trades well below its intrinsic value.
The lesson? When failure is cheap, move fast. When it’s expensive, protect yourself.
That’s why Parrish created a rule for himself: “make major decisions and then sleep on them before telling anyone.” He further writes:
[I]t turns out that sleeping on decisions by itself wasn’t enough. I added another element to the rule: before going to bed, I would write a note to myself explaining why I’d made the decision. Doing so allowed me to make the invisible visible. When I woke up in the morning, I’d read the note. More often than I’d like to admit, my best thinking from the day before fell short upon inspection in the harsh light of the morning. Sometimes I’d realize I really didn’t understand the problem as well as I thought I did.
6. Learn From Your Decisions
The best decision-makers don’t just act – they learn. They’re self-aware. And the best ones done judge the outcome – they judge the process. Parrish shares a common error: people often confuse luck with insight. If something works out, they assume they were right. If if fails, they blame the world. This is known as “resulting” – judging a decision by its result, not the thinking behind it.
Even a 90% good decision can fail 10% of the time. That’s not incompetence: it’s risk.
Instead, ask:
- What did I know at the time I made the decision?
- Did the thing I anticipated happening come about for the reasons I thought they would?
To sharpen this process, write down your thinking before making the decision. This makes invisible logic visible. You’ll spot gaps earlier. Others can offer feedback. And if things go wrong, you’ll know whether the fault was the call – or the luck.