Co-Founder Dating? Here’s how to “thin-slice” your way to the right decision

Sandro Tuzzo
6 min readJan 12, 2022


People will often tell you that being a co-founder at a startup is essentially like being in a “work-marriage,” and I would agree. But, just like with marriage, the failure rate is higher than you’d think- so it’s not uncommon for startups (despite having a solid idea, good traction, etc.) to still not end up surviving simply because the team falls apart. When it does happen, the fallout tends to start at the top, usually with the first relationship that brought it all together; with the co-founders.

We can all agree that finding the right co-founder is pretty important and there are a growing list of co-founder “matching” sites, curated networks, questionnaires to use, and best practices to follow- but it’s another thing altogether to figure out the right process for determining whether the relationship with your co-founder is going to be resilient enough to weather the tests that all startups face. I’ve had a couple of co-founders myself, and I help founders who are just starting to get things off the ground, so let me share some advice to help you increase your odds of maximizing success in finding the right partner to start your company.

Perhaps the best way to discuss the right approach to forming a “work-marriage” is to go back to marriage itself. FWIW, I also happen to have more than a fair amount of experience with forming and dissolving marriages (i’ve been married once before, now happily remarried, and I used to have a career as a divorce attorney). In fact, the best example that I can offer about how to vet a potential partner correctly, is to tell you the story of how I almost didn’t meet my wife (the woman to whom i’ve been married for over a decade and have two young children with) because I was using the wrong approach, and it was only by luck that I was able to stumble into a second chance to meet her again.

It was over a decade ago and online dating was just starting to be a thing. I was living in San Francisco, recently divorced, and probably more “active” in the dating scene than I should have been. Because I really didn’t know what I was doing, I went on a lot of dates and I came up with a “system” which I thought would “maximize” my odds of finding the right partner. Just my luck that the approach that I had chosen to use at the time that I first contacted my wife was the ill-advised “phone screen.”

In short, the theory was that I would use the dating site profiles to make a preliminary determination of whether we shared common interests, values, etc. and then, instead of meeting for a quick coffee, I would find a reason to have a phone call to “assess for fit” by just talking over the phone about random things. It was a terrible idea! Not only did it result in potentially the worst “false negative” of my life (my wife hates talking on the phone, as she reminds me of whenever we’ve had one too many drinks) but it didn’t really test for anything reasonably related to what constitutes a healthy marriage. We NEVER talk on the phone!

Fortunately for me, I got extremely luck and was able to get a second chance at meeting her, in person this time, by randomly recognizing her at a comedy show (I not only found her to be attractive, but she was eating Popeye’s fried chicken and telling jokes to her friends…so I had no choice but to fall for her). In all seriousness though, my point here is that if you structure your process for finding the right co-founder the right way- then you can save your luck for the other areas of your business that will really need it.

Don’t get me wrong, it’s very important to spend a good amount of time and energy preliminarily determining whether you and your potential co-founder align on some key items (a business idea, level of commitment, key values, etc.) and I highly recommend Gloria Lin’s questionnaire when you think you have identified somebody with potential. But I can’t stress enough that there is a real limit on how much useful and relevant information that you can gather by merely having conversations and filling out questionnaires. You need to start working on something and only then will things become clear.

The truth is, there is just too much information that you need to gather to see whether you can closely work with somebody, day in and day out for years on end, and actually working on a project together is the only strategy that I know of that gives you the highest yield for that critical information. Why is this the case? It has to do with the way that our brains process large amount of data, so bare with me as I go down yet another tangent to explain.

In Malcolm Gladwell’s seminal book Blink, he introduces our brain’s powerful ability to “think without thinking” which he calls “thin-slicing.” In describing how this works, he explains a few different scenarios where individuals (who were often highly educated and/or skilled in a particular field) were able to make critical decisions, using their gut instincts/intuition, with a very high degree of accuracy. These decision-makers would often not be able to articulate exactly why they came to their conclusion- but they would instead refer to having a hunch or a strong opinion on which they knew that they could rely.

Gladwell went on to argue, rather convincingly, that we are all capable of making very quick inferences about the state, characteristics, or details of an individual (or situation) by finding patterns in events based only on “thin slices”, or narrow windows, of experience. This is why project-based co-founder “dating” can be such a useful tool. When working on a project together, you not only get to see each other’s skills in action, but you get to absorb so many other critical subtleties that inform each of you much more deeply as to what kind of person you could be forging this very critical relationship with.

For instance, while it’s probably reassuring to see your potential co-founder assemble an impressive spreadsheet on a particular topic- it would be equally as important for you to be able to assess some of the more nuanced reactions that he/she/they had when, for example, they responded to a potential ambiguity in their data, brainstormed with you on the significance of what the data meant for the business plan, or maybe suggested another task that they could perform which would further the goals of the project. It doesn’t really matter what they do actually, it’s more about how they do it- and you can only really see that in action and unscripted.

In summary, my advice to you is this: After you do your initial vetting for fit, etc.- try to start working on a project together as soon as possible before you make your minds up on partnering for the long term and you’ll be in a much better position to make the right decision. Looking for a co-founder is not easy, it can take time and there are a lot of things to consider. We all need a little luck from time to time, but you rarely get that second chance (that I was lucky enough to get) to forge some of our key life partnerships. Good luck!



Sandro Tuzzo

I’m a recovering attorney, current entrepreneur and consultant to startups and early stage teams.