👋 Hey, it’s Sundar! Welcome to experiMENTAL: a weekly newsletter on B2C Marketing & data science how-to guides, frameworks, and stories from 15 years including early Uber.

All startups are created in chaos, but the beauty is in wrangling that chaos. When there’s organized chaos and a method to the madness, that’s when we create progress. While there’s a ton of content around WHAT to measure, there isn’t enough on HOW. That’s why the first time I saw Libby Weissman’s growth sprints, I was blown away by the structure of it.

Libby is a Fractional CMO and a brilliant B2C Marketer, bringing together her experience leading the Caviar Marketing team through the DoorDash acquisition & COVID pandemic, building Marketing from scratch at Realm (a seed-stage renovation marketplace) to acquire the first 50k customers, and supporting 15+ clients in her consulting practice over the past three years.

She’s also a featured guest on my upcoming podcast and an all-around kind person. Below, she shares the framework she uses to help founders find an audience for their product and build a repeatable customer acquisition playbook.

Libby’s Growth Sprints (✏️ to Libby)

For B2C startups still figuring out their Marketing playbook—what I call discovery Marketing — running a structured experimentation process is an absolute must. (Emphasis on “structured” here: this is what helps you avoid throwing a lot of things at the wall and not getting any closer to the answer.)

Just as product, design, and engineering teams work in “sprints” to tackle key customer problems, Marketing and cross-functional growth pods can run “growth sprints” to test customer hypotheses and accelerate learning.

This process has helped me:

• Identify a more compelling positioning for a food subscription company, dropping cost per add-to-cart from $60 to $15.

• Unlock the right ad hooks and patient onboarding experience for a telehealth business, decreasing new patient CAC from > $3,000 to < $500.

• Uncover a highly motivated customer segment for a functional medicine provider, reducing cost per lead from $5 to $1.50.

How do the growth sprints work?

Designed to help us learn faster, Growth Sprints are a monthly process of running Marketing experiments against customer hypotheses.

One question I often get from those new to discovery Marketing is: “Why focus on learning? Shouldn’t we be focused on results?”

The answer is simple: faster learning is the fastest way to better results. I always return to my favorite analogy from Reforge: growth is a game of Battleship.

• On one side of the board are us marketers, making guesses about what our customers want and placing pegs to track what we’ve learned.

• On the other side are our customers and the secret roadmap to building a profit-generating, long-lasting business.

• We focus on learning because as we understand more about how customers react to our Marketing, we get more thoughtful about where to place our next pin.

• Ultimately, this leads us to better results—or, in the case of Battleship, sinking our opponent’s boat.

There are 3 key phases to my Growth Sprints process:

1. Establish Customer Hypotheses: Anchor your experiments in customer problems, not Marketing ideas.

2. Run Experiments: Test your hypotheses with clear, measurable experiments.

3. Extract Learnings: Analyze results and refine your next steps based on what you uncover.

Establishing customer hypotheses

So you have this business problem you’re trying to solve … but I hate to break it to you: your customers DGAF about your business problem. All they care about is their problems 🤷‍♂️ 🤷‍♀️ 

The first step in the Growth Sprints process is to connect your business goals to customer motivations.

Here’s an example from a client I worked with in the allergy space:

• Business problem → Increase booking CVR from 1.5% to 4%

• Customer problem + barrier → I need relief for my allergies, but I don’t believe going to the allergist will make anything better. It’s not worth my time.

• Hypothesis → We believe customers are distrustful of new solutions, preventing them from taking the first action of booking an appointment.

By starting with a clear hypothesis, you’re grounded in the realities of customer behavior rather than making assumptions based on your company’s perspective.

Generate Ideas

Now you’re thinking like your customers. But there are many ways you might be able to test this hypothesis … where should you start?

Brainstorm ways you can get a signal on your hypothesis and prioritize your ideas using your best judgment, just like picking where to drop your peg in Battleship.

For the allergy company, here’s how we turned the hypothesis into testable experiments:

Hypothesis → We believe customers aren’t booking because they distrust new solutions.

• Experiment #1 → Add statistics to the top section of the landing page citing clinical trials and efficacy data.

• Experiment #2 → Use patient testimonials in ads and on the landing page to highlight initial skepticism and eventual satisfaction.

• Experiment #3 → Add a pop-up for traffic about to abandon: “Many of our patients have tried everything else and were ready to give up before finding us. Your first appointment is covered by insurance. Will you give us a try?”

Extract Learnings

At this point, you’re making great progress and you feel confident that you have the right experiment to start with. So what’s next?

You’ll want to scope out the experiment, set a success KPI, and make sure you’re set up to measure the KPI. After the test wraps, take the time to analyze and extract learnings … think of this as studying the game board after each bomb to take in the new piece of context and re-evaluate what you know.

Here’s an example of how we set up the measurement for one experiment.

Example Experiment: Add statistics to the top section of landing page citing clinical trials and statistics on efficacy

• Success Metric: % Traffic Start Booking Flow

• Measurement Approach: A/B Test

• Ways to Extract Learnings: Segment the data by ad creative or ad source; watch HotJar recordings; analyze heat maps and scroll depth.

The key is to treat each experiment as a piece of a larger puzzle, using insights to guide your next move. Each learning brings you closer to unlocking your growth playbook.

When you combine all these elements, you have a systematic approach to finding your footing in the unpredictable world of startup Marketing.

By focusing on faster learning, grounded in clear customer hypotheses, you can identify what works and iterate quickly. Think of it as a structured version of trial and error—designed to maximize learning while minimizing wasted effort.

How Do I Set Up Growth Sprints?

A co-worker once called me a “marketer with an engineer’s brain” due to my obsession with process. Although I wholeheartedly agree that the most important thing for startups is finding and maintaining momentum, I wholeheartedly disagree that the best way to generate momentum is by moving fast at every turn.

We make a lot of mistakes when we move too fast, and we waste valuable time. This is why I love process.

Here are five rituals that form the foundation of this process:

1. The Brainstorm: Monthly sessions to generate ideas and think creatively about solving customer problems.

2. The Roadmap: A living document tracking in-progress, live, and completed experiments.

3. The Roadmap Standup & Review: Frequent check-ins (15-minute standups and weekly reviews) to keep experiments moving and uncover insights. Here’s my typical agenda for each.

4. The Experiment Doc: A template to ensure experiments are well-designed and results and learnings are tracked. Here’s the template I use.

5. The Strategy Review: Monthly sessions to zoom out, reassess hypotheses, and align your strategy with what you’ve learned. Here’s the outline I use for a monthly recap to ground our strategy review sessions.

When you bring all these rituals together, here’s what a month of growth sprints looks like:

By combining these rituals into a structured sprint cycle, you’ll create a rhythm of testing, learning, and iterating that drives meaningful growth.

Growth Sprints balance the need for speed with the discipline required to avoid costly mistakes, making them a powerful tool for startups navigating the chaos of early-stage Marketing.

Common Pitfalls to Avoid

After running this process at multiple startups, I’ve noticed a few pitfalls:

#1 Getting disconnected from customer problems.

Many marketers tend to think “idea-first” rather than customer-first. They have an idea for an ad or an email based on some inspiration from a brand they admire or someone else in the company, and they rush to implement it without thinking through how it connects back to the customer problem they’re trying to solve.

For example, I reviewed an experiment proposal from a lifecycle marketer who was launching a plain-text format email that simulated an email from a real person. The hypothesis was “Text-only emails have higher engagement and conversion”. We worked together to revise the hypothesis to “We believe that customers are overwhelmed with decision fatigue and building their first order is too complicated. Offering 1-on-1 support from a real person to place their first order will help them convert”, rewrote the email, and saw improved engagement.

#2 Not writing stuff down!!!!

No one remembers what they did last week, nevertheless what they did last month. This is why the “Experiment Doc” is my favorite of all the rituals. Not only does it create a very helpful paper trail for when you inevitably are analyzing performance and need to remember what tests were live when, but it also forces discipline around thinking through the test design and taking time to analyze results. This is where the magic happens!

I sometimes face resistance to writing things down from small teams who are so busy that this feels like extra “paperwork”. I had been working with a healthtech client for a few months who fit this category. After a few nudges, I convinced them to start logging their experiments and this was the email I got back:

“I wish we had been doing this since I founded the company!! This has made it so much easier for us to understand swings in our numbers and get smarter about what to do with our Meta ads. Thank you!”

#3 Forgetting to zoom out

The reason I focus on monthly sprints is to add a natural break to pause and reflect. Once you get into the groove of launching experiments and iterating based on the results you see, you can get lost in the weeds.

For example, I recently launched a new website for a client. We saw that our lead conversion went down after launching the site, and I spent a couple of weeks experimenting with the landing page design and CTA placement to try to fix it before I realized I needed to zoom out and go back to our original hypothesis. The new site's goal was to educate potential customers on our services better and build legitimacy and therefore gain trust. During my monthly recap, I took a step back and looked at the whole funnel and realized that although lead conversion was much lower, lead to enrollment was over 2x higher than previously. The site effectively qualified out lower intent leads and made the patient enrollment process more efficient. Net-net, a win!

Conclusion

Running Growth Sprints is a powerful way to unlock your startup’s potential. By focusing on customer hypotheses, disciplined experimentation, and actionable learnings, you can uncover what works and build a scalable growth playbook. Ready to dive in? Start small with one sprint, and let the learning begin.

Growth isn’t about finding a silver bullet but building a system that consistently uncovers what works.

Whether you’re working to uncover your ideal positioning, improve ad performance, or optimize onboarding, Growth Sprints gives you the tools to connect customer needs to business outcomes.

Wrapping up (✏️ back to Sundar)

To learn more about growth sprints, reach out to Libby via LinkedIn. Also, you should definitely subscriber to her newsletter. Just the name itself is a nerdy little play on functions.

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