# Audit grid position bias per provider

> Grid position is a reported, provider-specific selection lever, so you record your rendered on-screen position per engine to avoid mistaking a position swing for a content win or loss.

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- **Affects (funnel stage):** Choice
- **Evidence:** reported
- **Confidence:** High
- **Impact:** 3/3
- **Status:** active
- **Last verified:** 2026-07-08

## Per-platform status

Undocumented platforms show "unknown" - honest unknowns, never invented.

| Platform | Status | Notes | Source |
| --- | --- | --- | --- |
| ChatGPT | unknown | Not documented by this platform. | - |
| Gemini / Google AI Mode | unknown | Not documented by this platform. | - |
| Perplexity | unknown | Not documented by this platform. | - |
| Copilot | unknown | Not documented by this platform. | - |
| Claude | unknown | Not documented by this platform. | - |

## Evidence and sources

- [ACES (arXiv:2508.02630)](https://arxiv.org/abs/2508.02630) (2026-07-08)

## How to act on this

When results render as a grid, record your on-screen position per engine alongside the win/no-win result and look for correlation with signals you changed.

### Related checklist items
- [Audit where you land when an agent renders results as a grid: position bias is strong and provider-specific.](https://agentmint.net/tools/agent-selection-checklist/#b-measurement-05) (Selection)

### Related signals
- [Defined agent win-rate measurement](https://agentmint.net/signals/agent-win-rate-measurement/)
- [Re-test after every major model update](https://agentmint.net/signals/retest-on-model-updates/)

## Notes

Based on ACES (arXiv:2508.02630), a controlled agent-shopping simulation, not measured real-world sales.