In short
ROI puts the gain from an activity against what it cost. The formula is (return minus cost) divided by cost. An ROI of 200 percent means one franc became three. The number is only as sound as its two halves — and in marketing it is usually the return that is uncertain, not the cost.
Why the number is so often wrong
Because costs get captured completely and returns do not. Ad spend and fees sit in the ledger; the job that arrived three months later through a referral sits nowhere attributable.
The bias is systematic: channels with long paths get understated, channels with short paths overstated. Reallocate budget on that basis and you amplify the measurement error rather than the result.
What belongs on the cost side
Not only the agency invoice. Internal time too: three hours a week reviewing content, at an internal rate of CHF 120, is around CHF 1'500 a quarter that appears in no campaign report.
An honest calculation needs both. Otherwise you are comparing an activity with external cost against one with internal cost — and the internal one wins every time, because its price is invisible.
The more honest number for an SME
Instead of one ROI across everything: cost per enquiry and cost per job, split by source. Both are measurable without assumptions as soon as a CRM carries enquiries through to close.
Only once those two are stable across several months does an ROI say anything. Before that it is a snapshot with three decimal places.
How we handle it
We work with cost per enquiry because it is measurable without assumptions, and we label the share that cannot be attributed as exactly that: unattributable.
Where the measurement chain reaches the signed job, we run it all the way — which requires the link between website, ads and CRM.
Related terms
A term in your quote that nobody explained?
In a strategy call we translate the offer in front of you — even when it did not come from us.