“It’s not the y-intercept that matters. It’s really the slope that matters.” - David Hsu

Your slope in whatever you’re doing in life is more important than your y-intercept.

Knowing this helps you understand how fast you move and learn is more important than where you begin.


A little bit of slope makes up for a lot of Y-intercept.

So at a mathematical level this is an obvious truism. You know if you have two lines, the red line and the blue line and the red line has a lower Y-intercept but a greater slope then eventually the red line will cross the blue line.

And if the Y-axis is something good, depending on your definition of something good, then I think most people would pick the red trajectory over the blue trajectory (..unless you think you’re going to die before you get to the crossing point).

So in a mathematical sense it’s kind of obvious. But I didn’t really mean in a mathematical sense, I think this is a pretty good guideline for life also. What I mean is that how fast you learn is a lot more important than how much you know to begin with. So in general I say that people emphasize too much how much they know and not how fast they’re learning…

So I think this is a really interesting concept you can apply in a lot of different ways. And the key thing here I think is that slow and steady is great. You don’t have to do anything heroic. You know the difference in slopes doesn’t have to be that great if you just every day think about learning a little bit more and getting a little bit better, lots of small steps, its amazing how quickly you can catch up and become a real expert in the field.

01/13/2012. From a lecture by Professor John Ousterhout at Stanford, class CS140

  • From Sam Altman

    • “What’s you number one piece of hiring advice?”

    • “Hire for slope, not Y-intercept. This is actually my number one piece of life advice.”

  • Deciding to Go Big with David Hsu of Retool (podcast)

    • How to evaluate a startup @ 4:00

    • CA: Look at where they are now. Ask them about their goals and what they’re working on and check back in a month or two to see how much the progressed with their product and how many customer they found. Just kinda want to look at their progress.

    • DH: It’s not the y-intercept that matters. It’s really the slope that matters.

  • “A little bit of slope makes up for a lot of y-intercept” on HN

    • Good points. I would add to his last point though that hiring at least one person with a high y-intercept can increase the slope of your other hires significantly. (It’s a lot easier to learn something quickly if you have someone around who already knows a lot about it.) And people who both know a lot and learn quickly are expensive and rare, so I expect the optimal hiring process would look for a large percentage of relatively inexperienced fast learners, along with a small (but non-zero) percentage of more experienced people, even if they aren’t likely to develop as quickly. (Perhaps consultants would fit well in that role too.) - tempestn
  • Bring Keng on Slope vs Y-Intercept

    • The basic idea is you want to be the red line and not the blue line. From one of his lectures (emphasis mine)

    • I’m sure this isn’t the first time you’ve heard something along the lines of “be a lifelong learner” or “learn something new everyday”. There are so many variations on this cliche that it’s not really that interesting anymore but that doesn’t mean it’s not good advice.

    • Focusing on “slope” is hard though. Sometimes it’s a grind. But that’s not unlike most things in life. The people who can “grind” away and focus on the “slope” are ultimately the ones who are setting themselves up for success. Definitely not sexy (it is math after all), definitely not romantic, just the reality.

  • JD Ross on Keith Rabois betting

    • Many people talk about betting on a person’s growth rate vs experience. Keith actually hires and invests this way.