Last-touch attribution gives 100% of the credit for a conversion to the last marketing touchpoint the customer interacted with before converting. If someone sees a CTV ad, then later clicks a search ad to buy, last-touch credits the search click and assigns zero credit to the CTV impression. This systematically undervalues CTV because CTV advertising is non-clickable — a viewer cannot click a TV screen — meaning CTV impressions almost never appear as the last touchpoint, even when they drove the awareness that started the purchase journey.
For India CTV advertisers, last-touch models create a structural problem: reports showing CTV driving zero conversions are often not evidence that CTV is not working — they are evidence that the attribution model cannot see CTV contribution. What to do instead: (1) Run incrementality tests (geo holdout or user holdout) to measure causal effect directly; (2) Use multi-touch attribution models that distribute credit across all touchpoints; (3) Measure brand lift separately to capture awareness effects; (4) Compare site traffic and branded search volume in markets where CTV is running vs. where it is not. Last-touch is appropriate for direct-response channels where clicks are the primary action. It is structurally unsuitable for CTV.
Full guide
For a complete explanation, read: Last-touch attribution for CTV: why it fails and what to use instead