Many marketers mistakenly use attribution models for precise instructions. Instead, they should be used directionally to understand which channels are generally performing better, without treating the data as absolute truth that dictates every specific action.
To gauge the real impact of a campaign, isolate a small percentage of your audience (a "holdout group") from all marketing. The difference in conversion rates between this group and the targeted audience reveals your actual performance lift, moving beyond simple conversion metrics.
To understand a specific channel's effectiveness (e.g., out-of-home), concentrate spend in one geographic area. By comparing metrics like branded search volume in that area against a pre-campaign baseline, you can measure the channel's incremental lift, though this method can be expensive.
While complex attribution models have their place, a simple field on your forms asking customers how they found you provides invaluable qualitative data. This self-reported information offers a direct line of sight into which channels are truly resonating with your audience and driving action.