Most marketing measurement stops at“this might be the cause.”This is about getting past that.
I'm Andrei Popescu. Seven years buying paid media, on budgets from €500 to €200,000 a month. I write here about the methods that answer the questions a dashboard leaves open — which channels actually cause sales, whether a campaign changed anything, where the next euro stops paying off.
Every method gets the same treatment: how it works in plain words, the maths unpacked, where it lies to you, and a notebook you can run on your own data. The working is shown so it can be checked.
The writing
All posts →Marketing mix modelling · 15 min read · Interactive · Video
How much should I spend on each channel — and where does the next euro stop paying off?
A cost-per-sale tells you where sales happen, not where the next euro works hardest. Marketing mix modelling learns a diminishing-returns curve per channel and reads the return on the next euro — with a range on every number.
Experiments · 13 min read · Interactive
Is this channel actually driving sales — or would those sales have happened anyway?
Attribution tells you which channels show up near your sales; it cannot tell you which caused them. A geo-holdout switches a channel off in some regions and reads the difference — the closest a marketer gets to proof.
Attribution · 14 min read · Interactive
Which marketing channels actually drive sales — not just show up at the close?
Last-click hands every sale to the final touch and starves the channels that start journeys. Markov removal-effect attribution scores each channel by how far conversions fall when it is taken out.
How I show a number
Illustrative — drag the slider
A figure without its range is an opinion wearing a decimal point. Every number in every post here arrives with how far it could be off, and where it came from.
8 weeks of data: too little to measure. We estimate, and keep the range wide and honest about it.
Did the in-store sales come from the paid campaigns?
If offline conversions are not connected, online spend and in-store revenue never meet in one place — and no amount of modelling fixes a join that does not exist.
- What would settle it
- Point-of-sale data joined on date and store, or a sales export you can line up against spend.
- Until then
- Report the online conversions with their range, and leave the in-store link open rather than guess at it.
Measured — straight from the data.Modelled — a model stands between, shown with its interval.Estimated — inferred from thin data, widest range.
About the name
Stochastic describes an outcome that carries randomness — something you can state as a distribution, never as one certain number. Strata are layers.
Marketing results arrive in layers: the channel, the audience, the week, the thing a competitor did on a Tuesday. The name is a standing reminder that any figure here is one layer read off a stack — and that quoting it without its range would be exactly the omission this site exists to argue against.
Get in touch
I take on freelance paid media and measurement work, and I answer questions about anything published here. Email is the whole system — no form, no newsletter, nothing that follows you around.
Also on LinkedIn.