A campaign can register an impression in its systems and yet lack all the signals needed to accurately reconstruct what happened on the viewer’s device.

In CTV, the answer depends, among other things, on how the ad is inserted and how its measurement is implemented.

With CSAI (Client-Side Ad Insertion), the client-side player is involved in requesting and playing ads, as well as reporting ad events.

With SSAI (Server-Side Ad Insertion), ads are integrated into the video stream on the server side. This can provide a smoother playback experience, but it introduces specific measurement challenges, as certain events may be reported by the ad insertion infrastructure rather than verified directly on the device.

Where does the challenge lie?

• Delivery does not equal playback. The fact that a server has selected and delivered a creative does not, on its own, prove that the ad played correctly.
• A recorded event does not always mean independent verification. It is important to know which system generates the signal, what event it represents, and whether it can be independently verified.
• Measurement depends on integration. Standards such as VAST and the Open Measurement SDK (OM SDK) help structure ad delivery and verification, but their effectiveness depends on proper implementation and the level of support available in each environment.

When diagnosing a campaign, therefore, simply comparing the final impression counts is not enough. We need to understand what each system counts, where the signals are generated, and what happens between ad insertion and playback.

In CTV, technology is essential, but the real value lies in the technical expertise required to integrate and implement it correctly, as well as to interpret the resulting data and performance.