What is incrementality testing and do I actually need it?
The short answer
Incrementality testing measures whether an ad actually caused a sale that wouldn't have happened anyway, by holding out a control group (geo or audience) and comparing results, it's the only way to know if you're paying for demand you were already going to capture. You need it once retargeting and branded search make up a meaningful share of spend, since both are notorious for claiming credit for purchases that would have happened organically. If you're pre-Rs 10 lakh/month in spend, skip it for now and focus on getting blended CAC and CAPI right first.
A quick summary to orient you. The real value is below: the resources worth your time, from people who've actually done it, not us.
Here are the resources
Hand-picked from around the web, each with a note on why it earns your time. India-specific ones carry a badge.
Why we picked it
The clearest explanation of incrementality testing available, with practical guidance on running a geo holdout test yourself before paying for an enterprise incrementality tool.
Why we picked it
A current, practical rundown of what actually broke with attribution post-iOS14 and the realistic fixes (server-side tracking, first-party data) rather than nostalgia for pixel-only tracking.
Why we picked it
A privacy-compliant, statistically grounded alternative to pixel-based attribution, worth understanding even if you don't buy it, because MMM is becoming the operating standard post-iOS14.
Why we picked it
A leading marketing-mix-modeling-based attribution platform that doesn't rely on user-level pixel tracking, worth evaluating once platform-reported numbers stop being trustworthy enough to make budget calls on.
