Brand-search share does not measure incrementality. It describes a targeting category; incrementality asks what would have happened without the advertising.
Branded Search often captures people who already know the business. Non-brand Search and Shopping can reach people comparing unfamiliar products. Neither label, by itself, identifies which orders the ad caused.
The earlier argument that the criticism was “96% wrong” because brand search was “4%” confused a share claim with a causal result. There is no universal four-percent denominator that proves the rest of an account's spend incremental.
The useful next question is account-specific: which campaign or product group are we evaluating, against what counterfactual, for which business outcome and period? Attribution credit, new-customer labels and an iROAS study from another population are distinct forms of evidence.
Use the long-form incrementality framework to compare holdouts, matched designs and directional indicators. Keep uncertainty and contribution economics visible. A well-structured non-brand campaign is a hypothesis about additional profitable demand; it still needs a defensible measurement design.
Take the idea further
Read the incrementality framework