Master Your Growth with Our Hypothesis Kit to Drive Results

You know that feeling when you're running A/B tests but your hypotheses are all over the place? Yeah, we've all been there. That's exactly why the Hypothesis Kit exists – and it's become one of the most useful frameworks for anyone serious about conversion optimisation.

The story behind the kit

The Hypothesis Kit didn't just appear overnight. It came from real frustration in the trenches of optimisation work. Craig Sullivan, a conversion optimisation legend, saw teams struggling with weak hypotheses that led to mediocre tests and unclear results.

Craig's been in the optimisation game for years, working with major brands and watching the same patterns repeat: teams would jump straight into testing without thinking through their assumptions properly. They'd run tests, get results, but couldn't explain why things worked or didn't work.

So he created a simple framework to fix this mess.

Why hypotheses matter more than you think

Before we dive into the kit itself, let's talk about why this matters. A good hypothesis isn't just academic fluff – it's your roadmap for learning. When you write "I think changing the button colour will increase conversions," you're not really setting yourself up to learn anything useful.

But when you write "Because mobile users are struggling to see the CTA button (based on heatmap data showing low engagement), if we increase the button size and contrast, then we'll see a 15% increase in mobile conversions," now you're cooking with gas.

How the Hypothesis Kit evolved

The beauty of the Hypothesis Kit is that it keeps getting better. Craig didn't just create it and walk away – he's been refining it based on real-world use.

The original framework

The first version was pretty straightforward. It focused on the basic "Because/If/Then" structure that forces you to think through your logic. This was already a huge improvement over most teams' random testing approaches.

Version 2 gets more practical

Hypothesis Kit 2 added more structure around measurement and success criteria. Craig realised that having a good hypothesis was only half the battle – you also needed to be crystal clear about how you'd measure success.

This version started pushing teams to think about:

• What specific metrics they'd track

• How they'd know if the test was actually successful

• What they'd learn even if the test "failed"

Version 4: the current standard

The latest version (V4) is where things get really interesting. It's not just about writing better hypotheses anymore – it's about creating a complete testing strategy.

V4 includes frameworks for:

• Prioritising which tests to run first

• Connecting individual tests to bigger business goals

• Building organisational knowledge over time

What makes this kit different

Here's what I love about the Hypothesis Kit: it's practical. Craig didn't create some theoretical framework that looks good in presentations but falls apart when you try to use it. This thing was built by someone who's actually running tests and dealing with real business constraints.

The kit forces you to answer uncomfortable questions:

• What evidence do you have that this is actually a problem?

• How will you know if your solution worked?

• What will you do with what you learn?

Most teams skip these questions and wonder why their testing programmes don't drive real business impact.

Getting started with your own Hypothesis Kit

If you want to start using this framework, don't try to implement everything at once. Pick one element – maybe just the basic "Because/If/Then" structure – and use it for your next few tests.

Pay attention to how it changes your thinking. You'll probably find yourself digging deeper into data before jumping into tests. You'll start noticing assumptions you didn't even know you were making.

That's the whole point. The Hypothesis Kit isn't just about writing better hypotheses – it's about building better thinking habits that compound over time.

The framework works because it's based on how optimisation actually works in the real world, not how we wish it worked. And that's probably why it's become the standard for so many teams who are serious about growth.

Growth Method is the GrowthOS built for marketing teams focused on pipeline — not projects. Book a call at https://cal.com/stuartb/30min.

"We are on-track to deliver a 43% increase in inbound leads this year. There is no doubt the adoption of Growth Method is the primary driver behind these results."

Laura Perrott, Colt Technology Services