Not at the level of a person. Halo effect is a modeled relationship between OOH activity and your other channels' performance. No device is followed from a billboard to a Facebook click.
What is modeled, and how
We take your connected channels' performance history, build a counterfactual prediction of what those channels would have done without OOH in market, and measure the deviation during the campaign. It is the causal lift method pointed at channel metrics instead of sales.
Because it is privacy agnostic by construction, working from aggregate channel performance rather than user identity, it is unaffected by the signal loss that damaged device-level measurement.
What halo is not
No de-duplication: if a person saw your billboard and clicked your Facebook ad, halo does not know that and does not claim to.
No multi-touch attribution: AdQuick does not run multi-touch attribution in house and refers partners for it.
No user-level path: there is no journey view, and there is no data set in which one person's exposure and click sit on the same row.
Connection requirements and the failure modes
Google Ads, Google Analytics, and Facebook, authorized with view or read access. One Facebook ad account per campaign.
Twelve months of pre-period data in the test and control markets is preferred. That is a preference rather than a requirement: less history gives a weaker counterfactual, not an error. Causal lift carries a similar preference, wanting at least six months of history and ideally twelve.
The failure mode seen most often is connections that appear to save and then do not persist after account IDs are entered. If your halo results are empty, check the connection state before concluding that the campaign produced no halo.
The second failure mode is structural. Halo needs an active campaign on the connected channel in your OOH markets, plus activity elsewhere to compare against. No comparison, no result.
Reading the result
A positive halo says your connected channels outperformed the counterfactual while OOH was live in those markets. That is real evidence, and it is not proof of a mechanism. It does not tell you which creative, which unit, or which person.
It is also sensitive to anything else you were running. A large concurrent digital push in the same markets is not accounted for unless you tell us about it.
Common misconceptions
Myth: Halo shows a specific consumer moving from a billboard to a Facebook conversion.
Reality: It is a modeled market-level relationship. There is no user-level path.
Myth: Empty halo results mean OOH had no effect.
Reality: Check the account connections first. Persistence failures are a known issue.