How do I mention quantitative impact on resume when my experience has been for multiple years?

I'm confused: Does your team only have 1 metric that it measures itself up against overall and that's the only metric you have? You generally wouldn't put that on your resume.

So in general, this is how things work when teams have metrics:

1. There is some collection of key metrics that the team measures itself up against every quarter/half/year, setting a high-level goal to reach
2. Members of the team work on projects that try to increase the metric by some amount
3. For each project, its individual impact on the key metrics is measured
4. After each performance cycle, the team will add up all the impact across all the projects to figure out how well it did overall. Members who worked on projects contributing more to the goal tend to get rewarded more in performance review and promotion

#3 is the important one when it comes to what you put on a resume. You want to talk about individual projects and the impact they had, especially as senior engineers don't tend to own the entire goal on a team (that's usually reserved for Staff+).

As a very simple example, let's see you work on a growth & activation team. One of the core components these types of teams own is the onboarding flow. So let's say this happens:

• Your team's goal in H2 is to increase the number of user sign-ups by 2.5%
• 2 engineers on your team work on a project to decrease sign-up API call failures. This boosts sign-ups by 0.5%.
• You and a couple other engineers work on a project to add Google One Tap. It increases sign-ups by 2%.

On top of being able to claim that you worked on a project that contributed the lion's share of the goal for perf review/promotion, you can put something like "Added Google One Tap login to boost website sign-ups by 2%" or something. If you work on a major website that does 10 million sign-ups per year, you can also convert it into a number: "Added Google One Tap login to boost web sign-ups by 200,000+ annually".