Start here if you don't have a data team
You do not need a full attribution stack to get a real answer to "which marketing channel is working." You need three things, consistently applied: a way to tag where traffic came from, a way to track what that traffic turned into, and a cost number to compare it against.
The core idea: cost per customer, not cost per click
Clicks and impressions tell you a channel is active. They do not tell you whether it is worth the money. The number that answers that is customer acquisition cost (CAC): what you spent on a channel, divided by how many actual customers it produced.
| Metric | What it tells you | What it misses |
|---|---|---|
| Clicks / traffic | Is anyone engaging with the channel at all | Whether any of it converts to revenue |
| Leads / form fills | Is the channel generating interest | Whether those leads are worth anything once qualified |
| Customer acquisition cost | What it actually costs to win a real customer through this channel | Long-term customer value, unless you also track that separately |
A simple, no-tool way to do this
- Tag every campaign and channel with a consistent UTM parameter, so traffic source is visible in your analytics.
- Record the source/channel on every lead in your CRM, from the first touch you can capture through to closed revenue.
- Every month, divide what you spent on each channel by how many paying customers it actually produced - that is your channel-level CAC.
- Compare CAC across channels, not just volume - a channel with fewer, cheaper customers can outperform a channel with more, expensive ones.
When you outgrow the spreadsheet
This manual approach breaks down once you have enough channels, enough volume, or long enough sales cycles that spreadsheet tracking gets error-prone or too slow to act on. At that point, the next step is proper marketing attribution - and if your numbers already look inconsistent across platforms, start with why your marketing numbers don't match before adding more tooling on top.