The NSM Trifecta

One of the most common mistakes candidates make in success measurement questions is choosing a metric that sounds important, but is structurally incomplete.

Two examples show up over and over again: DAU and average actions per user. Both are useful. Both are meaningful. And neither is an acceptable North Star Metric on its own.

The reason is simple: each of them measures only one dimension of the behavior you actually care about.

A true North Star Metric needs to capture the total value the product is creating. To do that, it has to reflect both how many people are engaging and how deeply they’re engaging. If it only moves when one of those changes, it’s not a North Star—it’s a partial signal.

This is where the North Star Metric trifecta comes in.

The Trifecta

You can think of success measurement as a triangle. At the top of the triangle is the Total—for example, “Total Watch Time per Day.” This is the metric that represents overall success. It answers the question: how much of the core value is the product delivering right now?

At the bottom of the triangle are two supporting metrics. On one side is DAU, which measures the breadth of engagement. DAU tells you how many people are showing up, but it says nothing about what they’re doing once they arrive.

On the other side is average usage per user, which measures the depth of engagement. This metric tells you how intensely an individual user is engaging, but it completely ignores how many users there are.

The reason neither of these bottom metrics can serve as the North Star becomes obvious once you think about how they behave. If DAU is your North Star, then an increase in usage per user doesn’t move the metric at all. You could make the product dramatically better for existing users, and your “North Star” would stay flat. That’s a problem.

The opposite is true if you choose average usage per user. If your user base grows meaningfully but individual behavior stays the same, your metric doesn’t move. You’ve clearly created more value, but your supposed North Star can’t see it.

The Total avoids both of these failures.

Why the total is the NSM

The Total moves when either input changes. If more users show up, it goes up. If existing users engage more deeply, it goes up. In practice, the Total is simply the product of the two bottom metrics:

Total = DAU × average usage per user

That’s why the Total belongs at the top of the triangle. It’s the only metric that correctly reflects changes in both scale and intensity of engagement.

That doesn’t mean the bottom metrics are less important. In fact, they’re essential.

The Total tells you that the product is growing, but it doesn’t tell you why. You don’t know whether growth is coming from user acquisition, increased retention, or deeper usage by existing users. Keeping DAU and average usage per user as explicit supporting metrics allows a product manager to diagnose what’s driving changes in the North Star and respond appropriately.

Strong success measurement isn’t about picking a single number and ignoring everything else. It’s about choosing the right number to represent success—and the right supporting metrics to understand it.