Our favourite framework for making difficult “Do I Do It or Not?” decisions breaks them down into testing the underlying elements that matter most.
What is What Do You Need To Believe?
Many of the most important decisions we make are whether to do something or not: should we attend that university? Join that company? Launch that new product? Hire that new employee? Acquire that company? And so on.
The crux of What Do You Need To Believe is a combination of taking two steps:
- Identify the 3-5 foundational elements that must be true to make a larger decision true.
- Then ask ourselves how much we believe each of these elements will prove true: how much confidence do we have each element will play out as we believe/hope it will?
Therefore, we take the larger hypothesis or assertion - let’s say to join a specific company - and we break it down into the sub-assertions that need to be true to make that larger assertion true. It’s not only easier to test the sub-assertions than the overarching assertion, but it also lends itself to delegating to those with the relevant expertise: e.g., Team A will handle testing sub-assertion 1, while Team B will handle sub-assertions 2 and 3, etc.
Sticking with whether to join a specific company, everybody will have different elements that are important to them, but here’s an example of the criteria I (James) narrowed down to when considering full-time jobs last year following a Career Break:
- Does the Company’s Mission Matter To Me?
- Is the CEO and broader Executive Team World-Class?
- Is the Company Experiencing Hypergrowth?
This doesn’t mean other elements wouldn’t also play a role - e.g., the specific role or the company’s remote work policy - but it meant these three elements were the foundational elements I needed to believe were true (before I chose to pursue a fractional exec path instead of a full-time path, although my criteria don’t change much).
Regardless of the decision we’re making, the key to What Do You Need To Believe is pushing ourselves to only include the sub-assertions that really matter. We both know people who’ve created complex spreadsheets with dozens of colour-coded sub-variables to break down decisions like which graduate school to attend. Almost always, it overcomplicates the situation, and the hard work and the value is figuring out the 3 to 5 sub-assertions that matter and then doing the work to get confidence in testing whether each is true or false.
As parents of elementary school kiddos, here’s a bit of fun to showcase this framework:
When to Use What Do You Need To Believe?
One second Blueprint was 
The most common work-related 1-Way Door decisions tend to be talent-related - think joining a company or hiring somebody - or launching a new initiative - think changing branding, releasing a new product, or acquiring a company.
Although it’s less common, What Do You Need To Believe can equally apply in our personal lives: for example, from the micro of whether to send children to public or private school to the macro of whether to have children in the first place (who might be scared of dragons under their beds).
An important callout is that What Do You Need To Believe doesn’t mean the assertions we believe WILL prove to be true, it just means that we’d be making a good decision IF they do. For example, a VC fund may make an investment because it believes there’s a huge Total Addressable Market (TAM) and this tight-knit, talented team has a good chance to build out a differentiated product suite; after 36 months, the team may have self-imploded, and other competitors may have surpassed this company’s offerings, but that doesn’t mean the initial logic wasn’t right; it just means the assertions they believed in didn’t prove true in reality.
Therefore, identifying the sub-assertions is often reasonably quick, especially for structured thinkers, and the hard work is gathering and analyzing the data to get a crisp perspective on each one.
How do we use What Do You Need To Believe?
James:
I first learned What Do You Believe To Believe at Bain, which was one of the frameworks we used all the time; to this day, it’s in the Top 3 Tools I use most often. The most important lesson for me from Bain was forcing ourselves to narrow down to the fewest number of sub-assertions possible. For example, let’s imagine we’re deciding whether to acquire a company: in theory, as part of proving out a sub-assertion about revenue growing at X% CAGR, we could try to predict growth rates for every product line and every region or customer type: you can imagine dozens or even hundreds of rows in a detailed spreadsheet. But, in reality, most of the rows don’t really matter, and it usually comes down to going deeper to predict performance for the primary business line or two, usually only a handful of rows in that potentially complex spreadsheet.
The need to narrow down to what really matters reminds me of LinkedIn Co-Founder Allen Blue’s product framework, where he outlines whether a product is “Nice to Have” vs “Want to Have” vs “Need to Have” for its users (stickier, more successful products are rarely “Nice to Have”). Connecting to What Do You Need To Believe, it’s easy to list out 20 elements that are nice to have - e.g., when joining a company perhaps that it offers good food or a nice gym onsite - but harder and more important is to identify the 3-5 elements that are truly non-negotiable, getting the 80/20 right.
John:
A lesson I’ve learned over the years is to “trust the process to get you to a YES, but trust your gut if it tells you NO”. There are 2 gems of wisdom in this approach: first, don’t lower your standards by second guessing your bar; but also, if you set the bar in the wrong places, your “flight” instinct will kick in. Listen to it.
James:
Where was this advice 10 years ago? I’ve hired more than one person where the process said “Yes” but my gut told me “No,” and I trusted the process: my gut was right every time.
One of the most valuable elements of What Do You Need To Believe - and with some many frameworks - is they get everybody onto the same page. For example, returning to our example of acquiring a company, there may be 20 potential reasons to acquire a company and an equal number of reasons not to; this often leads to lots of opinions but not a shared logic that underpins the central deal hypothesis. What Do You Need To Believe narrows down everybody to the elements the decision-makers have aligned on as the most important to test.
John:
I recently joined a company that uses the “What Do You Need To Believe?” language quite often (ex-LinkedIners on the Exec team), and I’ve found it helps avoid paralysis and perfectionism to keep the company moving forward. With this framing, “beliefs” operate as theories that are validated by evidence but can also be adjusted over time. Our CEO is the first to admit when we believed something was true that wasn’t. This honesty encourages you to constantly search for truth, test, adapt, and refresh your beliefs.
James:
What Do You Need To Believe has become a lens through which I see the world these days: less that I create a consulting-style Logic Tree and more that I always ask myself what are the two or three most important things I need to believe to are true to recommend Action X or pursue Option Y.
At the intersection of work and personal, when I decided to take a year-long career break in late 2022, this framework helped me narrow down. While there were many pros and cons, after digging in, I realized the only cons that really mattered were the lack of incoming cash flow and fear of the unknown; I didn’t believe either were strong enough cons, and while not everything went according to plan during my break (see below for my detailed write-up), my logic was correct and I don’t second-guess the decision to take a more extended career break.
Want to learn more?
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For What Do You Need To Believe specifically, our longtime LinkedIn colleague (and current COO) Dan Shapero wrote a short, clear article on the topic back in 2013 here.
If you want to go to the source of being MECE and using logic trees to outline the sub-assertions underneath What Do You Need To Believe, The Pyramid Principle by Barbara Minto (a McKinsey consultant in the mid-late 20th century) is the foundational book. Note, it’s a dry, tough read, so we’d recommend our Blueprint on 
Broadening further to decision-making in general, several Blueprints have dug in already:
The Priority Matrix (PMAT), again from Dan Shapero, is a great example of how to compare options - e.g., which new market to enter - by focusing on only two axis, how large each opportunity is (Size of Prize) and how confident we are we can compete successfully (Ability to Win).
Warren Buffett’s 5/25 Rule shares with What Do You Need to Believe a focus on identifying what’s truly critical vs what’s nice to have, in this case, in the context of being clear on our top priorities.
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