boltTLDR
Whitespark's analysis of 1.8M Google Business Profiles shows that specific primary categories, aligned additional categories, and complete profiles correlate with substantially better local rankings.
Whitespark founder Barry Schwartz analyzed 1.8 million Google Business Profiles across 4,209 categories to identify what drives local search success. The research confirms that choosing specific primary categories (e.g., "Electrician" vs. "Contractor") yields ~36% higher top-10 presence than generic ones, that targeted additional categories improve rankings by 6–17 positions, and that a five-point GBP Completeness index (based on website, description, hours, photos, and claimed status) correlates with 19-position average rank improvement from 0 to full completion. Whitespark notes that while correlation doesn't prove causation, the data clearly establishes that deliberate category selection and profile optimization are foundational to local SEO performance.