OTT vs CTV vs Streaming TV: What Each Term Means

OTT, CTV and streaming TV are often used as if they mean the same thing, but they describe different parts of the same picture. OTT (over the top) describes how content is delivered: over the internet instead of cable, broadcast or satellite, to any device. CTV (connected TV) describes the screen: a television connected to the internet. Streaming TV is the everyday phrase viewers use. This comparison is part of our paid advertising guide.

What each term describes

OTT is a delivery model. The term comes from broadcasting: content once sent over cable or satellite began to be delivered online, "over the top" of those networks. The industry body IAB defines OTT as live or on-demand video delivered directly to viewers over the internet. That covers ad-supported apps, subscription services and free streaming channels.

CTV is a device category. IAB defines connected TV as a subset of OTT: a television screen connected to the internet, either directly as a smart TV, or through a streaming device, a games console or a set-top box.

Streaming TV is consumer language. It has no formal industry definition. People use it to mean watching TV shows and channels through apps, usually on a TV. It is useful in conversation and vague in a contract.

IAB Tech Lab sums up the distinction in two rules: use CTV for a specific type of device, and use OTT for content.

Which screens each one covers

This is where the terms matter most for an advertiser. An OTT buy can run on a phone in a commuter's hand, a laptop on a desk or a TV in a living room. IAB states that OTT includes all devices and environments, and is not exclusive to CTV.

A CTV buy runs on televisions. IAB Tech Lab says plainly that mobile and desktop devices are not included under the term CTV. IAB UK adds that a CTV media buy can generally be assumed to run in a large-screen format.

If you've planned a TV commercial and the partner reports "OTT impressions", ask how many played on a TV. A 30-second spot designed for a living room plays very differently on a phone screen.

How ads are bought under each term

All three terms can describe the same programmatic marketplace. The difference is which slice of it you're buying.

In OpenRTB, the standard most ad exchanges use, every bid request carries a device type. Connected TV is its own value, separate from phones, tablets and computers, and set-top boxes have another. So a buyer can choose to bid only on TV screens, and a seller can report them separately. OpenRTB 2.6 also added ad pods for CTV, letting buyers bid on slots within a commercial break, and app identifiers for CTV app stores.

The app-ads.txt standard from IAB Tech Lab also covers connected TV app stores. It lets streaming apps list which sellers may sell their ad space, which helps buyers avoid unauthorized resellers.

"Streaming TV" isn't a buying term. If a proposal uses it, ask whether it means CTV only or OTT across devices.

Targeting and measurement

The screen changes what can be targeted and measured.

A TV is often shared by everyone in a home, so CTV targeting and reporting often work at household level rather than for one person. Location usually comes from the home's internet connection. Content targeting, by genre, channel or app, works much as it does in other video.

OTT across devices mixes household TVs with personal phones and computers. That widens reach but makes reports harder to compare: a completed view on a phone and one on a TV are counted the same way, yet they're very different experiences.

For either term, delivery metrics such as impressions and completion rate only tell you the ad played. To learn what it did, link the campaign to site visits, searches, calls and sales.

We cover that step by step in how to measure CTV ad performance.

What it means for your creative

A CTV ad is watched on the largest screen in the house, in the same breaks as commercials from big brands. It should be built for that: readable on a TV, clear in audio, and working without a click.

An OTT buy that includes phones needs creative that also works small. Text that reads well on a TV may be too small on a phone, and a phone viewer may be watching without sound. If your buy spans devices, check how the spot reads on each screen, or split the buy and the creative by device.

We explain how streaming ads are delivered and the specs buys can require in what OTT advertising is.

Which term should you choose?

Use the term that matches what you're buying.

Say CTV when you want television screens. Put it in the brief, and ask for delivery reported by device type, so you can see the share of impressions on TVs.

Say OTT when the device doesn't matter and the content does, such as a campaign that should reach people inside streaming services wherever they watch. Expect a device mix, and make creative that works on each screen.

Keep streaming TV for conversations with customers and colleagues outside advertising, and translate it into CTV or OTT before you brief a partner. If you'd rather have the buy defined, the spot produced and the campaign run in one place, our in-house ads team runs OTT and CTV campaigns alongside the creative.

These are terms, not products. Each is judged on the same five criteria, using IAB and IAB Tech Lab definitions and the OpenRTB standard.