Marketing overinvestment happens when channel spend keeps climbing after the economics stop supporting it. This matters because impression share only shows auction share, not whether growth or profit goals are being met. Without the right target, growth firms miss where ROAS drops below one, and profit firms miss where marginal profit turns negative. This video explains the two thresholds that define overinvestment, whether you’re optimizing for growth or profitability.
Why Marketing Overinvestment Starts With Watching the Wrong Metric
Marketing overinvestment starts with watching the wrong metric, because a number like impression share tells you how much of the auction you’re winning without ever telling you whether that spend still clears the bar your business actually cares about. In this video, John Wallace, CEO of LiftLab, explains that the first question in any overinvestment check isn’t about the channel at all, it’s about what the firm is actually optimizing for: growth or profitability. The two goals are related but not identical, and they point to different stopping rules.
A firm optimizing for growth typically targets an incremental ROAS of one, meaning incremental revenue matches the investment dollar for dollar. A firm optimizing for profit instead watches marginal profit, asking what one more dollar of investment returns at the current spend level, and aims to keep going until that marginal profit reaches zero. Both are legitimate, economically grounded strategies; the overinvestment problem shows up when neither threshold is being tracked at all, and impression share is filling the gap instead.
In this video, you’ll learn:
How to identify if you are overinvesting in marketing channels
Why relying on metrics like impression share can be misleading
The fundamental economic questions to ask marketing budget optimization
The core differences between optimizing for high growth versus profitability
How to calculate incremental return on ad spend and marginal profit
TIME STAMPFull Video Transcript: Spotting Marketing Overinvestment Explained
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In this video, LiftLab CEO John Wallace explains how to tell when a marketing channel is overinvested, using two different economic thresholds depending on whether the goal is growth or profitability.
[0:00 – 0:18] Addressing Marketing Overinvestment
A fundamental question that marketers ask themselves, and sometimes will ask me, is how do I ensure that I haven’t got an overinvestment in one of my marketing channels. Often that condition happens if we’re looking at the wrong metrics. I’ve seen brands that were focused on metrics like impression share or something like that.
[0:18 – 0:31] Economic Foundations of Optimization
In economics, we want to first ask the question: what are you trying to optimize for? And the most common suspects are going to be for growth or for profitability, and while these two metrics are related, they’re not identical.
[0:31 – 1:05] Strategic Goals: Growth vs. Profitability
For a high growth firm that’s optimizing for growth, one of the common targets that they’ll set is they want to get incremental revenue that’s equal to their investment, so they’ll run this to an incremental ROAS of one. A firm that’s optimizing for profit will look at the marginal profit; it’ll say, at the current investment levels, if I put another dollar, or unit, or euro in, what do I get in return, and they want to run that out to a marginal profit of zero. Two different strategies, both enabled by understanding the underlying economics, and you get to decide where you want to put the effort.
Key Lessons: Setting the Right Target to Avoid Marketing Overinvestment
Metric pitfalls: Overinvestment often occurs when teams focus on vanity metrics rather than underlying economic drivers.
Optimization strategy: Determining success depends on whether the organization is prioritizing rapid growth or operational profitability.
Growth targets: High-growth firms often aim for an incremental return on ad spend of one, where revenue equals the cost of investment.
Profitability focus: Firms optimizing for profit evaluate the marginal benefit of each additional dollar spent, targeting a marginal profit of zero.
