Incremental lift is the percentage increase in conversions or revenue caused specifically by your advertising, compared to what would have happened without it. It strips out sales that were going to happen regardless and shows only the effect your marketing created.
If 100 people would have bought from you anyway and your campaign pushed that number to 115, your incremental lift is 15 percent. Those extra 15 purchases are the ones your marketing actually caused. The original 100 were going to happen no matter what.
Why lift matters more than attributed conversions
Attribution models count how many conversions were associated with a touchpoint. Lift measures how many conversions would not have happened without that touchpoint. These are very different questions. A user who clicked an ad and then bought something was associated with that ad. But they may have bought the same day without ever seeing it.
Attribution gives you a number. Lift gives you a cause. Budget decisions should be based on causation, not correlation.
How incremental lift is measured
Lift is measured using a controlled experiment. You expose one group to the advertising and withhold it from a comparable control group. The percentage difference in conversions between the two groups, after accounting for any baseline differences, is the lift.
- Lift % = (Conversion rate of test group - Conversion rate of control group) / Conversion rate of control group
- Incremental conversions = Lift % x Total conversions expected in the market
- Cost per incremental conversion = Total spend / Incremental conversions
Absolute lift vs relative lift
Relative lift is expressed as a percentage improvement over the control group. Absolute lift is the raw percentage point difference. Both matter.
A campaign that lifts conversion rates from 2 percent to 2.4 percent has a relative lift of 20 percent but an absolute lift of 0.4 percentage points. Both are real ways to describe the same result, but relative lift can make a small absolute effect sound much larger.
Always report absolute lift alongside relative lift. Relative lift percentages without absolute context can overstate the business value of a campaign and lead to overinvestment in channels with low baseline conversion rates.
What good lift looks like
There is no universal benchmark for good lift. What is "good" depends on your conversion rate, your average order value, and your cost of advertising. A 5 percent lift on a high-value purchase may justify enormous spend. A 30 percent lift on a low-value purchase may still not be profitable.
The more useful comparison is across your own channels. Which channels produce the highest lift per pound spent? That comparison, grounded in experimental data, is the foundation of effective budget allocation.
Lift decay after a campaign ends
Lift is not permanent. When a campaign ends, the incremental effect diminishes over time as the advertising memory fades. Measuring lift decay, by continuing to track both groups after the campaign ends, tells you how long your advertising continues to produce an effect.
Understanding lift decay helps you make better decisions about campaign frequency and flight schedules. A channel with rapid lift decay needs continuous presence to maintain effectiveness.
Is incremental lift the same as incremental ROAS?
No, but they are related. Lift is a percentage measure of the conversion or revenue difference caused by advertising. Incremental ROAS converts that lift into a revenue efficiency ratio by dividing incremental revenue by the spend that produced it. You need the lift figure to calculate the iROAS.
Can I measure lift without running an experiment?
Marketing mix models can estimate a channel's incremental contribution from historical data without running an experiment, but these are statistical estimates, not direct measurements. The most reliable lift measurement comes from a controlled experiment with a proper holdout group.
How often should I measure lift for each channel?
For major channels, aim to measure lift at least once a year and after any significant change in strategy, creative, or spend level. Lift can change as audience saturation increases, as competitors change their strategies, or as your own brand awareness builds. Historical lift measurements do not guarantee current performance.