Navigating Incrementality in Marketing Tests

What’s up everyone, today we have the pleasure of sitting down with Simon Lejeune, VP of Growth at Wealthsimple.

• (00:00) - Intro
• (01:16) - In This Episode
• (03:55) - How to Escape Local Maximum Traps in Growth Marketing
• (08:59) - Productive Laziness Mindsets
• (12:03) - The Psychological Trap of A/B Testing
• (15:55) - Balancing Clean Experiments with Bold Bets
• (18:43) - How to Use Incrementality to Measure Real Campaign Impact
• (22:32) - How to Approach Incrementality Without Large Data Sets
• (25:13) - The Best Use Cases for Incrementality Tests
• (29:58) - How to Handle ROI Conversations Without Slowing Down Growth
• (38:02) - Why Most A/B Testing Is a Waste of Time
• (47:17) - When Natural Language Becomes the Interface, Channel Expertise Stops Being a Moat
• (01:03:31) - How to Use Game Thinking to Stay Energized in Growth Roles

Summary: Simon Lejeune learned early that chasing small wins keeps growth teams stuck, a lesson that landed hard when Hopper’s CEO dismissed his price‑point test as a “local maximum” and pushed him toward ideas bold enough to reshape the business. That experience drives how he leads at Wealthsimple, where he tells teams to stop polishing the same hill and start climbing new mountains by deleting work that doesn’t matter, cutting projects when the lift is negligible, and measuring true incrementality with one simple question: “What would have happened if we didn’t do this?” He believes AI is accelerating this shift, turning deep channel expertise into a commodity and making curiosity, speed, and ruthless prioritization the real competitive advantages. Growth, in his view, belongs to teams who can abandon the comfort of optimization and pursue experiments big enough to change the trajectory.

About Simon

Simon Lejeune is a seasoned growth leader with over a decade of experience scaling some of North America’s most recognized tech brands. Currently VP of Growth at Wealthsimple, he drives client and asset growth across products like Trade, Crypto, Cash, Invest, and Tax. Before that, Simon founded Mile End Growth, a boutique agency delivering strategy, creative, and media buying for startups, and led user acquisition at Hopper, where he managed multimillion‑dollar budgets and built one of the most sophisticated in‑house ad automation engines in travel tech. His career began at Busbud and Nomad Logic, where he directed growth marketing and developed new revenue‑generating spin‑offs.

Local Maximum vs Global Maximum
How to Escape Local Maximum Traps in Growth Marketing

A local maximum trap happens when teams keep optimizing small features that look like wins but cap long-term growth. Simon uses the metaphor of being blindfolded on uneven terrain. You walk in every direction until each step feels lower, then assume you have reached the peak. When you take off the blindfold, you see you are standing on a hill while a much larger mountain waits in the distance. Many growth teams spend months, sometimes years, stuck on those hills.

Simon experienced this lesson in an uncomfortable way. During his final interview at Hopper, CEO Fred Lalonde asked him what he would change first to grow revenue in the app. Simon answered with what felt like a logical idea. He suggested testing different price points for the $5 tip option, maybe $4 or $6, to find the best revenue point.

“He looked at me and said, ‘That’s literally a local maximum, and I do not want you doing that,’” Simon recalled.

That feedback forced Simon to change his perspective. He proposed a more radical idea: building a separate app that would use Hopper’s flight data to surface ultra-cheap Ryanair-style deals under five euros. It sounded risky and unconventional, but Lalonde loved it. Simon left that meeting understanding that real growth often comes from bigger, more disruptive ideas that challenge the current model instead of refining it.

Growth teams can apply this lesson by actively questioning whether their experiments drive material change or simply polish what already exists. Regularly evaluate whether you are optimizing features, pricing, or flows when the real opportunity may be entirely new product lines, bold pricing experiments, or acquisition channels that look nothing like what you use today.

Key takeaway: Incremental optimizations create comfort but rarely drive exponential growth. Audit your current priorities and identify one experiment that pushes far beyond incremental gains. Focus on ideas that reimagine your product, acquisition model, or customer experience. That way you can escape local maximum traps and open paths to growth that small experiments will never reach.

Productive Laziness Mindsets

Simon challenges his team to delete more work than they refine. “The fastest way to do something is not to do it,” he said. He encourages what he calls “productive laziness,” which means questioning why a task exists before sinking hours into improving it. Many growth teams fill their calendars with recurring meetings and busywork that provide comfort but little actual impact. Simon wants his team to hunt down and remove the 80 percent of work that clogs up progress.

“You could probably not do 80 percent of what you’re doing, and you need to take the time to find it.”

He distinguishes between local and global maxima. Local maxima are small, incremental wins that stack up over time. They create efficiency, but they rarely transform outcomes on their own. Simon shared a story from Wealthsimple where his team used a simple AI-driven prompt to quickly generate FAQs for new promotions. It only improved one process by a few percentage points. Combined with other similar fixes, it meaningfully reduced the time from campaign idea to launch. These small process wins compound into real operational speed.

Simon points out the trap many teams fall into when these tweaks become the entire focus. He calls out A/B testing as the classic example. The industry celebrates small lifts in conversion rates, yet the promised gains rarely translate into significant growth. “If you’ve had that many wins,” he said, “your conversion rate should be 300 percent by now.” Experienced operators know that most of these improvements exist only in reports, not in the top-line numbers.

He pushes for a balance between incrementalism and bold redesigns. Teams need to ask hard questions: Does this process deserve to exist? Does this experiment meaningfully impact the business? Would rebuilding this system create more value than optimizing it? Those are global maximum questions, and they require a willingness to break away from the comfort of small wins to pursue something transformative.

Key takeaway: Use incremental process improvements to accelerate execution, but regularly pause to audit whether the work itself creates meaningful business impact. Remove tasks, experiments, or processes that do not clearly connect to growth. That way you can free up the capacity to pursue global maximum opportunities that drive measurable, lasting results.

The Psychological Trap of A/B Testing

Local maximum thinking happens when teams equate motion with progress. Simon describes this as the pattern of chasing a string of small A/B test wins while nothing meaningful shifts in the business. Every tweak produces a minor lift, enough to justify the next experiment, yet the bigger picture remains stagnant. The illusion of progress feels convincing in the moment, which is why so many teams stay stuck in it.

He experienced this firsthand at Wealthsimple. The team wanted to answer a straightforward question: should they push new users toward onboarding ...