September 2022  
  
I recently told applicants to Y Combinator that the best advice I could give
for getting in, per word, was

> Explain what you've learned from users.

That tests a lot of things: whether you're paying attention to users, how well
you understand them, and even how much they need what you're making.  
  
Afterward I asked myself the same question. What have I learned from YC's
users, the startups we've funded?  
  
The first thing that came to mind was that most startups have the same
problems. No two have exactly the same problems, but it's surprising how much
the problems remain the same, regardless of what they're making. Once you've
advised 100 startups all doing different things, you rarely encounter problems
you haven't seen before.  
  
This fact is one of the things that makes YC work. But I didn't know it when
we started YC. I only had a few data points: our own startup, and those
started by friends. It was a surprise to me how often the same problems recur
in different forms. Many later stage investors might never realize this,
because later stage investors might not advise 100 startups in their whole
career, but a YC partner will get this much experience in the first year or
two.  
  
That's one advantage of funding large numbers of early stage companies rather
than smaller numbers of later-stage ones. You get a lot of data. Not just
because you're looking at more companies, but also because more goes wrong.  
  
But knowing (nearly) all the problems startups can encounter doesn't mean that
advising them can be automated, or reduced to a formula. There's no substitute
for individual office hours with a YC partner. Each startup is unique, which
means they have to be advised by specific partners who know them well. [1]  
  
We learned that the hard way, in the notorious "batch that broke YC" in the
summer of 2012. Up till that point we treated the partners as a pool. When a
startup requested office hours, they got the next available slot posted by any
partner. That meant every partner had to know every startup. This worked fine
up to 60 startups, but when the batch grew to 80, everything broke. The
founders probably didn't realize anything was wrong, but the partners were
confused and unhappy because halfway through the batch they still didn't know
all the companies yet. [2]  
  
At first I was puzzled. How could things be fine at 60 startups and broken at
80? It was only a third more. Then I realized what had happened. We were using
an _O(n 2)_ algorithm. So of course it blew up.  
  
The solution we adopted was the classic one in these situations. We sharded
the batch into smaller groups of startups, each overseen by a dedicated group
of partners. That fixed the problem, and has worked fine ever since. But the
batch that broke YC was a powerful demonstration of how individualized the
process of advising startups has to be.  
  
Another related surprise is how bad founders can be at realizing what their
problems are. Founders will sometimes come in to talk about some problem, and
we'll discover another much bigger one in the course of the conversation. For
example (and this case is all too common), founders will come in to talk about
the difficulties they're having raising money, and after digging into their
situation, it turns out the reason is that the company is doing badly, and
investors can tell. Or founders will come in worried that they still haven't
cracked the problem of user acquisition, and the reason turns out to be that
their product isn't good enough. There have been times when I've asked "Would
you use this yourself, if you hadn't built it?" and the founders, on thinking
about it, said "No." Well, there's the reason you're having trouble getting
users.  
  
Often founders know what their problems are, but not their relative
importance. [3] They'll come in to talk about three problems they're worrying
about. One is of moderate importance, one doesn't matter at all, and one will
kill the company if it isn't addressed immediately. It's like watching one of
those horror movies where the heroine is deeply upset that her boyfriend
cheated on her, and only mildly curious about the door that's mysteriously
ajar. You want to say: never mind about your boyfriend, think about that door!
Fortunately in office hours you can. So while startups still die with some
regularity, it's rarely because they wandered into a room containing a
murderer. The YC partners can warn them where the murderers are.  
  
Not that founders listen. That was another big surprise: how often founders
don't listen to us. A couple weeks ago I talked to a partner who had been
working for YC for a couple batches and was starting to see the pattern. "They
come back a year later," she said, "and say 'We wish we'd listened to you.'"  
  
It took me a long time to figure out why founders don't listen. At first I
thought it was mere stubbornness. That's part of the reason, but another and
probably more important reason is that so much about startups is
[counterintuitive](before.html). And when you tell someone something
counterintuitive, what it sounds to them is wrong. So the reason founders
don't listen to us is that they don't _believe_ us. At least not till
experience teaches them otherwise. [4]  
  
The reason startups are so counterintuitive is that they're so different from
most people's other experiences. No one knows what it's like except those
who've done it. Which is why YC partners should usually have been founders
themselves. But strangely enough, the counterintuitiveness of startups turns
out to be another of the things that make YC work. If it weren't
counterintuitive, founders wouldn't need our advice about how to do it.  
  
Focus is doubly important for early stage startups, because not only do they
have a hundred different problems, they don't have anyone to work on them
except the founders. If the founders focus on things that don't matter,
there's no one focusing on the things that do. So the essence of what happens
at YC is to figure out which problems matter most, then cook up ideas for
solving them — ideally at a resolution of a week or less — and then try those
ideas and measure how well they worked. The focus is on action, with
measurable, near-term results.  
  
This doesn't imply that founders should rush forward regardless of the
consequences. If you correct course at a high enough frequency, you can be
simultaneously decisive at a micro scale and tentative at a macro scale. The
result is a somewhat winding path, but executed very rapidly, like the path a
running back takes downfield. And in practice there's less backtracking than
you might expect. Founders usually guess right about which direction to run
in, especially if they have someone experienced like a YC partner to bounce
their hypotheses off. And when they guess wrong, they notice fast, because
they'll talk about the results at office hours the next week. [5]  
  
A small improvement in navigational ability can make you a lot faster, because
it has a double effect: the path is shorter, and you can travel faster along
it when you're more certain it's the right one. That's where a lot of YC's
value lies, in helping founders get an extra increment of focus that lets them
move faster. And since moving fast is the essence of a startup, YC in effect
makes startups more startup-like.  
  
Speed defines startups. Focus enables speed. YC improves focus.  
  
Why are founders uncertain about what to do? Partly because startups almost by
definition are doing something new, which means no one knows how to do it yet,
or in most cases even what "it" is. Partly because startups are so
counterintuitive generally. And partly because many founders, especially young
and ambitious ones, have been trained to win the wrong way. That took me years
to figure out. The educational system in most countries trains you to win by
[hacking the test](lesson.html) instead of actually doing whatever it's
supposed to measure. But that stops working when you start a startup. So part
of what YC does is to retrain founders to stop trying to hack the test. (It
takes a surprisingly long time. A year in, you still see them reverting to
their old habits.)  
  
YC is not simply more experienced founders passing on their knowledge. It's
more like specialization than apprenticeship. The knowledge of the YC partners
and the founders have different shapes: It wouldn't be worthwhile for a
founder to acquire the encyclopedic knowledge of startup problems that a YC
partner has, just as it wouldn't be worthwhile for a YC partner to acquire the
depth of domain knowledge that a founder has. That's why it can still be
valuable for an experienced founder to do YC, just as it can still be valuable
for an experienced athlete to have a coach.  
  
The other big thing YC gives founders is colleagues, and this may be even more
important than the advice of partners. If you look at history, great work
clusters around certain places and institutions: Florence in the late 15th
century, the University of G�ttingen in the late 19th, _The New Yorker_ under
Ross, Bell Labs, Xerox PARC. However good you are, good colleagues make you
better. Indeed, very ambitious people probably need colleagues more than
anyone else, because they're so starved for them in everyday life.  
  
Whether or not YC manages one day to be listed alongside those famous
clusters, it won't be for lack of trying. We were very aware of this
historical phenomenon and deliberately designed YC to be one. By this point
it's not bragging to say that it's the biggest cluster of great startup
founders. Even people trying to attack YC concede that.  
  
Colleagues and startup founders are two of the most powerful forces in the
world, so you'd expect it to have a big effect to combine them. Before YC, to
the extent people thought about the question at all, most assumed they
couldn't be combined — that loneliness was the price of independence. That was
how it felt to us when we started our own startup in Boston in the 1990s. We
had a handful of older people we could go to for advice (of varying quality),
but no peers. There was no one we could commiserate with about the misbehavior
of investors, or speculate with about the future of technology. I often tell
founders to make something they themselves want, and YC is certainly that: it
was designed to be exactly what we wanted when we were starting a startup.  
  
One thing we wanted was to be able to get seed funding without having to make
the rounds of random rich people. That has become a commodity now, at least in
the US. But great colleagues can never become a commodity, because the fact
that they cluster in some places means they're proportionally absent from the
rest.  
  
Something magical happens where they do cluster though. The energy in the room
at a YC dinner is like nothing else I've experienced. We would have been happy
just to have one or two other startups to talk to. When you have a whole
roomful it's another thing entirely.  
  
YC founders aren't just inspired by one another. They also help one another.
That's the happiest thing I've learned about startup founders: how generous
they can be in helping one another. We noticed this in the first batch and
consciously designed YC to magnify it. The result is something far more
intense than, say, a university. Between the partners, the alumni, and their
batchmates, founders are surrounded by people who want to help them, and can.  
  
  
  
  
  
  
  
  
  
  
  
**Notes**  
  
[1] This is why I've never liked it when people refer to YC as a "bootcamp."
It's intense like a bootcamp, but the opposite in structure. Instead of
everyone doing the same thing, they're each talking to YC partners to figure
out what their specific startup needs.  
  
[2] When I say the summer 2012 batch was broken, I mean it felt to the
partners that something was wrong. Things weren't yet so broken that the
startups had a worse experience. In fact that batch did unusually well.  
  
[3] This situation reminds me of the research showing that people are much
better at answering questions than they are at judging how accurate their
answers are. The two phenomena feel very similar.  
  
[4] The [Airbnbs](airbnbs.html) were particularly good at listening — partly
because they were flexible and disciplined, but also because they'd had such a
rough time during the preceding year. They were ready to listen.  
  
[5] The optimal unit of decisiveness depends on how long it takes to get
results, and that depends on the type of problem you're solving. When you're
negotiating with investors, it could be a couple days, whereas if you're
building hardware it could be months.  
  
  
  
**Thanks** to Trevor Blackwell, Jessica Livingston, Harj Taggar, and Garry Tan
for reading drafts of this.  
  

