You can’t measure your brand without measuring your competitors

Here’s a question I like to ask brand leaders: your sales are up 5% this year. Are you doing well?

Most people say yes. But what if your competitors are up 20%? Then the category is growing four times faster than you are, and you’re quietly losing market share. You’d be celebrating a year in which you fell behind, and nothing in your own numbers would tell you.

And yet almost every brand measurement tool is built to look at one brand: yours.

The numbers that predict growth are all relative

The most robust findings in marketing effectiveness have one thing in common. They’re about your brand compared with everyone else’s.

Start with share of voice. John Philip Jones set out the pattern in the Harvard Business Review back in 1990, and Les Binet and Peter Field later tested it against the IPA’s effectiveness data. Brands whose share of voice runs ahead of their share of market tend to grow. On average, ten points of excess share of voice is worth about half a point of market share a year.

You can’t calculate that without knowing what your competitors spend.

Then share of search. When Binet introduced it at the IPA’s EffWorks conference in 2020, his finding was striking: “share of search can predict market share, sometimes up to a year ahead.” When James Hankins later looked at 30 cases across 12 categories and seven countries for the IPA, share of search tracked about 83% of a brand’s share of market on average.

Share of search is, by definition, your searches as a share of everyone’s in the category. That’s precisely what makes it so powerful: it’s built on the competitive set.

Your growth lives in your competitors’ customers

Byron Sharp’s work at the Ehrenberg-Bass Institute adds a deeper reason. Brands in a category share their buyers with each other, broadly in line with their size. Your customers also buy your competitors. Their customers also buy you.

Which means growth, for a challenger especially, mostly comes from winning a little more of the people who currently buy someone else. If you’re not watching what those brands are doing, you’re not watching where your growth will come from.

Why most measurement looks inward

It isn’t laziness. It’s how the tools were built.

A brand tracker surveys people about your brand, and maybe a handful of rivals, once a quarter. Your competitors certainly don’t answer it. A marketing mix model looks at your own spend against your own sales, with competitors as a control variable at best. Dashboards show the data you own.

So the one comparison that predicts growth is the one most teams can’t see.

What a competitive view tells you that nothing else does

When you can watch your whole competitive set on the same lens, a different set of questions opens up.

• Who’s doubling down, and who’s pulling back? A rival going quiet is an opening: the same spend suddenly buys you a bigger share of voice.
• Where is the white space? A channel, a moment or a buying occasion nobody in the category owns.
• Is your gain real? Did you grow, or did the category grow and you just kept pace?
• Who’s coming up behind you? A small brand gaining momentum shows up in search and conversation long before it shows up in a share report.

What to do this quarter

1. Define your competitive set the way your buyer would. Not the brands you’d like to be compared with, but the ones on the shelf next to you and in the same search results.
2. Measure them the same way you measure yourself. Same signals, same cadence, same lens. A like-for-like view is the only one that holds up.
3. Track share, not absolutes. Share of voice, share of search, share of conversation and, increasingly, share of AI recommendations.
4. Bring it to every big decision. Budget, launch timing, channel mix. The question is never just “is this working?” It’s “is this working better than what they’re doing?”

You don’t win a category on your own scoreboard.