---
id: "claim-stable-assortment-u-shape"
type: "claim"
source_timestamps: ["§ Distance has a U-shaped impact", "¶10", "¶11"]
tags: ["retail-category", "distance-decay"]
related: ["concept-inverted-u-shape", "concept-billboard-effect", "contrarian-distance-decay"]
confidence: "high"
testable: true
speakers: ["Bowen Luo", "Bhoomija Ranjan"]
sources: ["tail1"]
sourceVaultSlug: "hbr-seg-tail1"
originDay: 1
articleStem: "hbr-tail-115-location-based-advertising"
sourceUrl: "https://hbr.org/2026/03/a-better-strategy-for-location-based-advertising"
sourceTitle: "A Better Strategy for Location-Based Advertising"
---
# Ad effectiveness follows an inverted U-shape for stable assortments

**Claim (author confidence: high; testable):** For retailers with **stable product assortments** (home improvement, grocery, drugstores), advertising effectiveness peaks at **moderate distances (≈ 4 to 14 miles)** and is weakest at **very close distances (< 4 miles)** — due to the [[concept-billboard-effect]] — and at **very far distances (> 14 miles)** due to travel costs. This is the [[concept-inverted-u-shape]] donut, and it contradicts linear distance decay (see [[contrarian-distance-decay]]).

## Verification status (enrichment)
- **Directional logic — consistent** with habit-formation and retail gravity-model research: habitual, already-aware close customers show lower marginal ad lift; marginal areas show more.
- **Exact inverted-U-of-ad-lift-by-distance-band pattern — proprietary:** open literature documents distance as a predictor of *store choice*, not *ad responsiveness per band* in these categories. No independent study demonstrating this specific pattern was located.