# Performance Marketing Metrics That Actually Matter

> ROAS, CPA, MER and the handful of metrics that should drive decisions, plus the vanity numbers founders should stop reporting.

- URL: https://wearegrova.com/en/insights/performance-marketing-metrics-that-matter/
- Language: English
- Published: 2026-06-02
- Author: Mert Aydın
- Category: Performans
- Tags: roas, cpa, mer, metrics
- Publisher: Grova (https://wearegrova.com/), an adviserlab. brand

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The metrics that matter in performance marketing are the ones that change a decision: ROAS, CPA, MER, contribution margin and conversion rate. Everything else, impressions, reach, likes, is context at best and distraction at worst. If a number does not change what you do next, stop reporting it.

## The five numbers worth watching

**ROAS (return on ad spend)** tells you revenue per unit of spend at the campaign or channel level. It is the day-to-day steering metric. **CPA (cost per acquisition)** tells you what a customer or lead costs, which matters most when margins are tight. **MER (marketing efficiency ratio)**, total revenue divided by total marketing spend, is the founder's metric: it shows whether the whole machine is profitable, not just one campaign.

Add **conversion rate** to see whether the site is doing its job, and **contribution margin** to make sure you are buying profit, not just revenue. A campaign with great ROAS on low-margin products can still lose money.

## Why platform ROAS lies (a little)

The ROAS inside Meta or Google is reported by the platform that wants more budget. Attribution overlap, view-through credit and last-click bias all inflate it. That is why MER matters: it is measured from your real revenue and total spend, so it cannot be gamed by attribution settings. A healthy pattern is strong platform ROAS and a MER that confirms blended profitability. When platform ROAS rises but MER does not, you are buying customers you would have won anyway.

## The vanity metrics to ignore

Impressions, reach, follower count and "engagement" feel good and decide nothing. They belong in awareness reporting, not in a growth dashboard. The test is simple: would this number make you increase, hold or cut spend? If not, it is vanity. For what to do when the real numbers slip, see [5 things to check when ROAS drops](/en/insights/5-things-to-check-when-roas-drops).

This is also where channels connect. Good [performance marketing](/en/#services) is wasted if the website converts poorly, so conversion rate and ad metrics have to be read together, not in separate reports.

## Frequently asked questions

**What is a good ROAS?**
It depends entirely on your margin. A 3x ROAS is excellent for low-margin retail and unprofitable for some products. Set the target from contribution margin, not a benchmark.

**ROAS or MER, which should I track?**
Both. ROAS steers campaigns day to day; MER tells you if the whole operation is profitable. Founders should watch MER above all.

**How often should I review these?**
Weekly for ROAS and CPA at the campaign level, monthly for MER and contribution margin at the business level.

This article is part of our guide to [working with a Turkey-based agency](/en/insights/working-with-a-turkey-based-agency).

Last updated: June 2026. If you want reporting that talks return instead of impressions, [start with a free analysis](/en/contact).