A Harvard business student and former advertising art director at General Motors released a research paper last month with car dealership ad spend in mind.

Automotive Retail Advertising in Crisis: Overlooked Liquidity Lever, which was published by Andrew Reutsky on Aug. 12, reports the first field deployment of Banner-VIN-Profit, which is an open-source attribution model tracing each ad to the VIN it sold and the profit it produced.

The model audited 100 listings on a “major retail platform” during a quarter at a midsize franchise dealership, the paper’s author said. What it found was that 62% of ad spend “carried no defensible link to a sale or a dollar of profit,” the author said in a news release.

“Advertising is among the largest discretionary expenses a dealership controls and the easiest to shed. When margins compress, every dollar a dealer cannot trace is trapped liquidity, and every dollar recovered from untraced spend is working capital — redeployable toward inventory, floorplan interest, or the channels that demonstrably convert. So advertising is cut first, but cut blind,” the news release said.

“For the nearly half dealership owners positioning to sell within the decade, the same opacity leaks into enterprise valuation. Advertising that shows its return becomes an audited liquidity lever: the last expense cut in a downturn instead of the first.”

For more information, visit EffectiveAutoRetail.com.