# How to measure CTV ads for a car dealership

> How a car dealership can tell whether streaming TV ads worked: the three kinds of numbers in a CTV report, how to set up a ZIP-code holdout, what to track at the store, and the questions to ask a vendor.

URL: https://brightmattersystems.com/research/how-to-measure-ctv-ads-for-car-dealerships/  
Published by Bright Matter (Bright Matter LLC). Author: Shannon McNeil, founder. Published 2026-11-06, updated 2026-11-06.

## The short answer

Measure streaming TV in three layers. What was delivered (households, frequency, apps, cost) is counted. What those households did afterward (site visits, leads, showroom visits) is matched through IP addresses and device graphs, so it shows correlation, not cause. Whether the ads caused anything only shows up against a holdout: ZIP codes or households that did not see the ads. Plan the holdout before launch.

## The three kinds of numbers in a CTV report

| Layer | Examples | How real it is |
|---|---|---|
| Counted | Impressions, households reached, frequency per household, completion rate, the apps the spot ran on, cost | Measured by the platform. Tells you the ads ran and where. |
| Matched | Website visits, leads and showroom visits from households that saw the spot | Inferred by matching IP addresses, device graphs and mobile location data to the exposed households. A correlation. |
| Caused | Extra calls, searches, visits, leads and sales compared with a holdout | The only layer that answers whether the ads changed anything. |

Vendor reports tend to lead with the counted layer because it always looks good. Completion rates on streaming run above 90% because most spots cannot be skipped, so a high completion rate describes the format, not the campaign.[^1] Some dealer CTV sellers leave clicks off their reports entirely, because most TV screens are not clickable and click numbers would describe a small slice of the audience.[^2]

## Set up a ZIP-code holdout before you launch

- **Pick comparable ZIP codes.** From the ZIP codes where your buyers and service customers live, choose a few pairs that look alike in households, sales history and distance from the store. One of each pair gets the ads; the other is held out.

- **Exclude the holdout ZIP codes** from the streaming targeting on every platform, and keep them out of any other new campaign during the test.

- **Record a baseline.** Four weeks before launch, log calls, branded searches, website visits, leads and showroom visits by ZIP code.

- **Run the flight for six to eight weeks.** Shorter flights rarely produce enough calls and visits to compare.

- **Compare the change, not the totals.** If exposed ZIP codes rose 20% over their baseline and holdout ZIP codes rose 5%, the difference is your best estimate of what the ads added.

A holdout will not be perfect: people drive across ZIP lines and see ads on other screens. It is still far better evidence than a report that only counts impressions.

## What to track at the store

| Metric | Where it comes from | Why it matters |
|---|---|---|
| Phone calls | Call tracking numbers on the website and in Google Business Profile | TV makes the phone ring first; calls are the quickest signal. |
| Branded searches | Google Search Console and Google Ads search terms for your store name | People search the store they just saw on TV. |
| Direct and organic site visits by city | Google Analytics 4 | A lift in the exposed area that the holdout does not show. |
| Vehicle detail page views | Google Analytics 4 and the Meta Pixel | Shopping intent, and the audience for Meta inventory ads. |
| Leads and showroom visits by ZIP | Your CRM and the showroom log | The comparison the holdout is built for. |
| Sales by ZIP | Your DMS, 30 to 90 days after the flight | The slowest signal and the one that pays for the next flight. |

When a vendor matches visits or sales back to exposed households, ask for the attribution window. Automotive vendors commonly use 14 to 30 days because buyers take time to decide.[^3] A longer window credits more visits to the ads; it does not make the ads work better.

## Questions to ask any streaming TV vendor

Dealers say reporting is where streaming TV breaks down: in a 2026 survey of dealership marketers, 64% said they were frustrated by reports listing channels they did not recognize.[^4] Ask these before you sign:

- Which apps and publishers will my spot run on, by name, and can I see that list every month?

- What is the CPM by app, and what is the minimum spend?

- Whose account is the campaign in, and can I log in and see it myself?

- Is frequency capped per household across all apps, or per app?

- Will you run a holdout, and who chooses the holdout ZIP codes?

- How are website and showroom visits matched to households, and with what attribution window?

- Can I export the log-level data when the contract ends?

## Questions dealers ask

### What is a good completion rate for a CTV ad?

On most streaming inventory the completion rate runs above 90% because the ad cannot be skipped, so it is not a useful measure of whether a dealership campaign worked. Look at households reached, frequency, and the lift in calls, searches and visits against a holdout instead.

### Can CTV advertising be tied to car sales?

Partly. Vendors can match households that saw the ad to later website visits, showroom visits or sales records, which shows correlation. To estimate how many sales the ads caused, compare exposed ZIP codes or households with a holdout that did not see the ads, and match sales by ZIP from your DMS 30 to 90 days after the flight.

### How long should a dealership run streaming TV before judging it?

Six to eight weeks, with a four-week baseline recorded before launch. Shorter flights rarely generate enough calls, leads and visits in the exposed and holdout ZIP codes to tell the difference.

### Do clicks matter for streaming TV ads?

Very little. Most television screens are not clickable, so clicks describe only the small share of impressions shown on phones or computers. Branded searches, direct visits and calls are better signals of response to a TV spot.

## Sources

[^1]: Matthew Chilinski, “CTV Advertising for Car Dealers: What Streaming Buys, What It Costs, and How to Read the Report,” Vulcanax, September 19, 2026. https://vulcanax.com/blog/ctv-advertising-for-car-dealers/
[^2]: Tad Beavers, “Streaming TV Advertising: The Complete Guide for Car Dealers,” Dealers United, August 6, 2026. Dealers United sells streaming TV to dealers. https://www.dealersunited.com/blog/streaming-tv-advertising-car-dealers-guide/
[^3]: Manmohan Singh, “CTV Advertising for Automotive Brands and Dealers,” LtvAdx, June 24, 2026. LtvAdx sells CTV advertising. https://www.ltvadx.com/blog/ctv-automotive-advertising-guide
[^4]: Pasch Group, “The Streaming Accountability Gap,” U.S. automotive OTT and streaming research report, August 2026. Survey of quality-screened dealership respondents. https://www.paschgroup.com/wp-content/uploads/2026/09/PaschGroup_Streaming_Accountability_Gap_2026.pdf

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Bright Matter runs streaming TV (CTV) and Meta ads for car dealerships, in ad accounts opened in the dealership's name. Book a call: https://cal.com/shannon-mcneil  Phone: 952-258-8222