Agencies measure whether GLSA is replacing other marketing channels by comparing total leads, unique customers, and revenue across all channels before and after GLSA performance changes. If GLSA leads increase while Google Ads, Yelp, organic search, or other sources decline, some customers may be shifting between channels rather than representing new demand.
To identify channel overlap, agencies should:
Track lead source and first-touch attribution in the CRM.
Deduplicate customers who contact the business through multiple channels.
Compare qualified leads, booked jobs, customer acquisition cost, and revenue by source.
Review total new customers, not just each platform’s reported leads.
Use controlled budget changes or holdout tests where practical to estimate whether GLSA is generating incremental demand.
Under the October 2026 GLSA setup, count calls, messages, and eligible bookings separately, then connect them to actual customer outcomes. The key question is whether GLSA increases total profitable customer acquisition or simply captures customers who would have converted through another channel.