How do you compare CTV inventory across platforms?

Three questions about inventory

1. Which apps and networks can the platform buy? Named publishers are more useful than a channel count.
2. Which inventory is exclusive? Some publishers sell their own inventory only through their own tools or chosen partners.
3. How is reach described? Household reach percentages are the vendor's own statements and use different bases.

What platforms publish

On the pages we read:

• Vibe lists "500+ channels" and names Disney+, ESPN, Hulu, HBO Max, Paramount Plus, Peacock, Roku Channel, Samsung TV Plus, LG Channels, Pluto TV, Tubi, Sling TV, Philo and YouTube, among others. Netflix and Prime Video are not listed on its channel page.
• MNTN states "direct deals with 150+" streaming networks reaching "99% of U.S. households", naming Peacock, HBO Max, Hulu, CBS and Bravo.
• tvScientific describes premium streaming and linear inventory reaching "93% of U.S. households through direct and programmatic buying", with a filterable list of publishers such as A&E Networks, AMC Networks and Bloomberg.
• Amazon lists exclusive inventory on Prime Video, Twitch, Thursday Night Football, Amazon.com and Fire TV, plus thousands of third-party sites and apps.
• StackAdapt lists partners including NBCUniversal, A+E Networks, Bell Media, Xumo, LG Ad Solutions and Philo, and "hundreds of networks".
• Disney Campaign Manager sells Hulu and Disney+ only.
• Universal Ads states reach of "up to 90% of US households" across "20+ of the biggest names in TV".
• Netflix sells its own ad-supported plan through its sales team and programmatic partners.

Walled gardens

A walled garden is a publisher that sells its inventory, and often its audience data, mainly through its own tools. Buying there can give unique audiences and first-party data, but results are usually measured inside the same garden, which makes cross-platform comparison harder. If a walled-garden publisher is essential to your plan, you may need its own tool alongside a multi-publisher platform.

Reading reach figures

"99% of households" and "93% of households" are not directly comparable unless the base (US TV households, streaming households, addressable households) is the same. Treat them as each vendor's description of potential reach, not delivered reach. Delivered reach depends on your budget, targeting and frequency cap.

A practical approach

1. List the three to five publishers your audience watches most.
2. Check each platform's published list for them. If one is missing, ask; catalogs change.
3. Decide whether you need exclusive inventory (for example Prime Video or Thursday Night Football) or broad reach across many apps.
4. In a pilot, ask for delivery reports by app so you can see where impressions actually ran.

How this shows up in our scores

Published inventory reach carries 10% of our weight. It rewards platforms that name publishers and state reach, and it is where publisher-owned platforms with exclusive inventory can score highest.