How to actually measure if a change worked

For a long time, the hardest part of any change I made wasn’t the change. It was not knowing whether it was working.

I’d switch a process at work, or a habit at home, and then sit in this fog of is this better, or am I just telling myself it’s better? You won’t know if you should keep using the new method or quietly slide back to the old one. I once described it to a friend as trying to bake a cake with no recipe and no timer — you keep opening the oven, poking it, hoping, and mostly you just let the heat out.

That fog is where most change quietly dies. Not in the planning. In the not-measuring.

We measure the wrong thing, then panic

Here’s the trap I fell into for years. I’d make a change and immediately go looking for the result. Revenue. Weight on the scale. The quarterly number. The big visible outcome.

And of course, three weeks in, the result hadn’t moved. So I’d conclude the change had failed — and abandon it right before it had any chance to work.

The mistake is one of timing. Results are lagging indicators. They report on a reality that already happened, weeks or months ago. By the time the number moves, the work that moved it is long done. If you steer only by lagging indicators, you’re driving while looking exclusively in the rear-view mirror.

Results tell you about the past. Behaviour tells you about the future. You need both, but you need to watch them on completely different clocks.

The fix isn’t a better dashboard. It’s a second clock.

Two clocks: behaviour weekly, results quarterly

This single reframe changed how I run every initiative now — in business, and honestly in my own body and home too.

Leading indicators are the behaviours and inputs you can see this week. Did the team actually use the new tool, or did they nod in the meeting and keep working the old way? Did I lace up and walk, three times, this week? Did the sales calls happen? These are the things you do, today, that cause tomorrow’s result.

Lagging indicators are the outcomes — the things you can only honestly judge over a quarter. Adoption translating to productivity. Walks translating to a number on the scale. Calls translating to revenue.

So the rhythm becomes simple:

Watch behaviour weekly. Is the new way actually being done? This is your early-warning system. It moves fast, it’s honest, and it tells you whether a result is even possible later.
Judge results quarterly. Give the outcome enough runway to actually show up. Measuring success too early gives you an incomplete, misleading read — and usually a premature funeral for a change that was just getting started.

In the book I list a whole pile of reasons change becomes “unmeasurable” — undefined objectives, no real metrics, thin data, and the one people miss most: timing and duration of measurement. Measuring too early is its own failure mode. You can’t weigh the cake while it’s still rising.

Why behaviour is the more honest signal

There’s a deeper reason to trust the weekly behaviour signal, and it’s the spine of nearly everything I write about here: the arc from effort to effortless. I think of it in four moves — discomfort, focus, resilience, mastery — and a new behaviour travels them in order.

It starts with discomfort: the new way is awkward, slower, a little embarrassing. Then comes focus — you aim limited energy at the one or two things that actually matter, instead of changing everything at once. Then the part everyone underestimates: resilience, the messy valley where the effort is high and the reward hasn’t shown up yet. And finally mastery — repetition makes the behaviour automatic, until it stops costing willpower and just becomes how you do things.

That last move is the whole point. A change has truly worked when the discipline that built it is no longer needed — when the new behaviour has become the easy default and nobody wants to go back to the old way.

So when you watch behaviour weekly, you’re really watching where on that arc you are. If the behaviour is happening more and more on its own — less reminding, less friction, less willpower each week — you’re climbing toward mastery, and the result is coming. Give it time. But if you’re still chasing people, nagging, propping it up every single week, you’re stuck in the valley. That’s your data. The behaviour hasn’t crossed into effortless yet, and you’ve found out months before the lagging number would have told you.

That’s the gift of the leading indicator: it lets you fix things while you still can, instead of doing a post-mortem on a dead initiative.

What this looks like in practice

I keep it almost embarrassingly simple now. For any change, I write down two things before I start:

The behaviour I’ll check every week — one or two leading indicators I can actually observe. Sessions logged in the new system. Workouts done. Conversations had. Things that are true or not true this week, no interpretation needed.
The result I’ll judge at the quarter — the lagging outcome the behaviour is supposed to produce, with an honest date I’m allowed to look at it.

Then I hold my nerve. When the result is flat at week three, I don’t panic — I look at the behaviour. If the behaviour is happening, I wait. If the behaviour isn’t happening, I stop asking “is this working?” and start asking “why is the right thing still so hard to do?” — which is a far more useful question, and one you can answer the same day.

Deming put it bluntly: “In God we trust. All others must bring data.” But the quieter, more useful cousin of that line is the one usually pinned on Drucker: “If you can’t measure it, you can’t manage it.” The trick is measuring the right thing at the right time — the behaviour now, the result later.

A lagging indicator confirms what you already did. A leading indicator tells you what to do next. If you only ever watch the first one, you’ll keep finding out you were wrong three months too late to fix it.

So before you start your next change — at work, in the gym, in the family — don’t just write down the result you want. Write down the behaviour you’ll watch on Friday. That weekly signal is the closest thing we have to a timer for the cake. (If you want the actual trackers and survey templates I use for this, they live in the free resources, and the full framework is in the book.)

Stop weighing the cake while it bakes. Watch the oven instead.