Know what’s
causing growth.
Know what to do next.
Your dashboards count conversions that would’ve happened anyway. Stella measures the revenue your ads actually caused, with rigorous holdouts and calibrated models that show their work. Not the cheapest. The most accurate, and we prove it.
Run a real holdout free · No credit card · Used by teams leaving legacy measurement vendors
Trusted by growth teams who left enterprise measurement vendors
Your dashboards are lying to you. Your CFO already knows.
You walk into the budget meeting with blended ROAS of 4.2 and channel wins on every slide. The CFO shares one chart: ad spend up and to the right, contribution margin down and to the right. Same period. “Walk me through this.” You can’t, because attributed revenue and actual revenue were never the same thing.
ROAS counts what would’ve happened anyway
Platforms grade their own homework. Attributed conversions aren’t caused conversions, and only one of those reconciles with a bank account.
Enterprise vendors hide their math
They charge $12–15K/mo and show you in-sample R² (trivial to fudge) while hiding the out-of-sample numbers that prove a model actually predicts.
Static incrementality decays
A 72% lift in January is 35% by April once creative fatigues and spend scales past what you tested. The number on the wall stopped being true, and nothing noticed.
We show the numbers that prove it. They don’t.
We’ve sat in your seat, running the budgets and answering for the results. So Stella is built on one rule: every claim comes with a receipt you can verify yourself. Real data scientists design your tests; the validation metrics are on the page, not behind a sales deck.
- Out-of-sample MAPE, R² and VIF shown on every model
- Geo holdouts designed for your business, confounders controlled
- Always-on calibration so the number stays true over time
From your data to decisions you can defend, in three steps.
Connect, or hand it over
Plug in your ad and sales data, or let our team run the whole engagement. Either way, setup is guided. No data science degree required.
Stella measures what’s causal
Holdouts, always-on incrementality, and calibrated MMM run together and recalibrate continuously, so the number is true today, not last quarter.
Act on what to do next
See where you’re saturated, where there’s headroom, and exactly how to reallocate. Do it yourself, or we do it for you.
See where every dollar stops working
Saturation curves show the spend level where returns flatten, so you stop pouring budget into the part of the curve that’s already maxed out, and move it where lift still exists.
Your true iROAS, recalculated every day.
No quarterly readout. Stella watches the budget changes your media buyers already make, runs causal impact on each one, and keeps incremental ROAS current, channel by channel.
The full budget picture, calibrated to your holdouts.
Channel contribution, saturation, and a budget optimizer that reallocates spend for maximum incremental return, calibrated against your real experiments, not vendor priors.
Connects to the platforms you already run
+ Shopify, Amazon & moreEach tool calibrates the next, and the loop compounds.
Holdouts calibrate your MMM. Both calibrate always-on. The incremental factor flows into MTA, then back to your ad platforms, so you optimize for incremental margin, not just purchases. The more you run, the sharper the signal.
Have us run it, or run it yourself.
Most brands want measurement done for them. That's our consultancy, and it's where most clients start. Not ready for done-for-you? The same platform is self-serve, from $6,000 down to free. There's an option for everyone.
$10k isn't for everyone. There's a plan for every budget.
Prefer to run it yourself? Same platform, self-operated: the full loop at $6,000, always-on incrementality from $3,000, attribution and surveys from $750, or start completely free. Walk down to the plan that fits.
- ✓Two media mix models and two holdout analyses every month
- ✓Upload a spreadsheet, get a real model back. No connectors to set up.
- ✓The same models we run for enterprise brands, not spreadsheet math
- ✓Ask questions about your results in plain English
- ✓Multi-Touch Attribution: see every touchpoint that leads to a sale
- ✓Ask buyers how they found you, right after they check out
- ✓Connect up to 5 sources (Shopify, Amazon, Meta, Google, TikTok) and stop pulling reports by hand
- ✓Run as many holdout tests and media mix models as you want, on data you upload
- ✓Ask questions about your results in plain English
- ✓Everything in Starter
- ✓Always-On Incrementality: a live view of how incremental every campaign is, updated daily, with no test to run
- ✓Holdouts and media mix models run straight off your connected data, region by region. Up to 7 sources, no more uploads.
- ✓See where the next dollar should go, and where a channel is already saturated
- ✓Ask your data questions from Claude, ChatGPT and your other AI tools
- ✓Everything in Professional
- ✓We send incremental conversions back to Meta, Google, TikTok and more, so their algorithms optimize for real profit instead of last click
- ✓All of your Stella data delivered into your own warehouse
- ✓Unlimited data sources
The questions skeptical marketers actually ask.
What is incrementality testing?
Incrementality testing measures the revenue that only happened because of your advertising, the lift you would lose if you turned a channel off. Unlike attribution or ROAS, which count conversions that may have happened anyway, incrementality isolates true causal impact, usually with a geo holdout where some regions see ads and matched control regions do not.
How is Stella different from legacy enterprise measurement vendors?
Two ways. First, transparency: we show out-of-sample MAPE, R², and VIF (the numbers that prove a model actually predicts), not just the in-sample R² that is trivial to fudge. Second, price and flexibility: full self-serve at $6,000/mo (about half a typical enterprise quote), a free tier for real holdout studies, or a fully managed engagement if you want us to run everything.
What is a holdout study?
A holdout (or geo holdout) is a controlled experiment: you keep ads on in test regions and off in matched control regions, then compare. The difference is causal lift. Stella designs the test/control split, accounts for confounders, and runs an ensemble of models so the result is defensible, even to a skeptical CFO.
What is continuous causal optimization?
Every causal estimate starts decaying the moment you measure it: creative fatigues, CPMs rise, spend scales past what was tested. Continuous causal optimization keeps your incrementality numbers current with always-on measurement and calibration, so you act on what is true today, not on a test from last quarter.
Do I need to be technical to use Stella?
No. Stella guides you step by step, and you can chat with it in plain language. If you would rather not touch it at all, our managed engagement does the holdouts, design, analysis, and reporting for you.
How much does Stella cost?
There is a free tier for proper holdout studies, a $750/mo starter with multi-touch attribution and post-purchase surveys, $3,000/mo to add always-on incrementality and run holdouts and media mix models straight off your connected data, and $6,000/mo to send incremental conversions back to Meta, Google and TikTok so the platforms optimize for profit. Support scales with the plan, from ticket support on Starter up to Slack and a named contact on Scale. Managed engagements start at $10,000/mo, where we run the whole loop for you.
Stop optimizing against numbers that aren’t true.
Run your first holdout free, or have our team build your continuous causal optimization loop end to end.