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A conversion is an action you designate as important to a business goal: a purchase, booking, suitable enquiry or call. Not every action carries the same weight. Opening a contact page suggests interest but is not a received message. Adding a product to a basket suggests intent but is not a completed sale. Decide what constitutes a real outcome before judging an ad campaign. [1]
Measure completion, not only progress
Walk through the customer journey and record the event after successful completion. For forms, verify that the message arrived. For purchases, check the confirmation and the order in the shop system. Remove duplicate events caused by reloading a page or firing the same tag twice. Two separate purchases by one customer may properly count twice, a confirmation page loading twice for one enquiry should not.
Consent choices and technical settings may leave some actions out of a report. Compare the figures with orders and sales records while protecting personal information. Explain discrepancies before moving budget in response to the numbers.
Understand three distinct measures
- Conversion rate relates recorded conversions to the selected interactions under the report’s definition.
- CPA, cost per acquisition or action, divides advertising spend by the number of conversions.
- ROAS compares revenue attributed to ads with the cost of those ads.
Suppose a hypothetical campaign spends €200 and records five purchases worth €800 in total. CPA per purchase is €40 and ROAS is 4, or 400%. Neither number is profit. Goods, production, delivery, returns, fees and labour also cost money. A low-margin business may lose money despite an apparently high ROAS. Decisions need the contribution left after variable costs and an understanding of fixed costs. [2]
Link enquiries to sales
For services, revenue may arrive weeks or months after the first enquiry. If a campaign generates twenty forms, find out how many are suitable, how many lead to proposals and how many become contracts. You can calculate cost per suitable enquiry and per won project. One large contract can shift the average considerably, so look at the distribution, sales cycle and customer fit as well.
Agree on simple qualification rules with the sales team. You need not send every personal detail to an advertising platform. Appropriately handled summary figures may be sufficient for a commercial decision. A clear definition of a suitable lead prevents every message from artificially improving the result.
Account for attribution and delays
A customer may see a social ad, search for the company later and finally buy after an email. Different reports can credit different touchpoints. Compare conversion definitions, attribution windows and the dates of clicks and purchases. Avoid adding figures from multiple platforms as if they necessarily represented different orders. [3]
With few purchases, a single day rarely supports a strong judgment. Examine trends, seasonal effects and price changes. If you alter the ad, website and measurement together, you will struggle to identify what affected the outcome.
Turn measurement into a decision
In a monthly view, record spend, completed conversions, lead quality, actual revenue and known costs. Separate directly measured facts from estimates. Then choose an action: fix measurement, improve the page, change the message or adjust budget. A metric is useful when it supports a reasoned decision, not simply because it looks impressive.
Special cases
For repeat customers, specify whether the first order or a longer customer relationship is being evaluated. Do not assume without evidence that every buyer returns. If returns are common, compare attributed revenue with confirmed revenue after returns. For seasonal products, use comparable periods where possible. Check the basic events before adopting complex value models. A simple, auditable calculation is more useful than a precise-looking number based on unreliable settings.
Frequently asked questions
When should a conversion be recorded?
Walk through the customer journey and record the event after successful completion. For forms, verify that the message arrived. For purchases, check the confirmation and the order in the shop system. Remove duplicate events caused by reloading a page or firing the same tag twice. Two separate purchases by one customer may properly count twice, a confirmation page loading twice for one enquiry should not.
How do conversion rate, CPA and ROAS differ?
- Conversion rate relates recorded conversions to the selected interactions under the report’s definition.
- CPA, cost per acquisition or action, divides advertising spend by the number of conversions.
- ROAS compares revenue attributed to ads with the cost of those ads.
Sources
Sources last checked: 12 October 2026.
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