Request:

We propose that Chrome provides the Ad Slot size(s) as an additional BTS signal.

Justification:

BTS will be able to filter ads and IGs based on the given width and height, hence, return fewer ad candidates with a higher quality. This will also decrease the size of exclusion packages that will be returned for the surviving ads.

Background:

Currently bts doesn’t have information about the slot size. Therefore Google Ads has to return creatives of all possible sizes (hundreds for GDA) to match the slot on the page. This causes several challenges:

• Limited capability to reduce the payload size.

• Prediction Models have to score the candidates of all sizes, which impacts the latency and the overall candidate scoring quality.

• Larger bts response size increases the auction latency.

Limitation:

Considering multiple slots on pubpages scenario when the HTTP cache caches trusted DSP response, we have to be accountable for keeping the cache hit rate unimpacted.

Proposal:

Given that the potential impact on cache hit rate requires experimentation, we suggest making the following parameters configurable via auction configuration:

• Bts receives a list of all slot sizes available on the publisher page as a concatenated comma separated string in each bts request. This allows Google Ads to optimize the bts response for certain slot sizes while maintaining cache hit rates.

• Bts receives an additional signal for a certain slot size. This allows Google Ads to optimize the bts response for a specific ad slot size, making the request itself lightweight.

• Bts does not receive slot size information. This option will help other bts to keep the current specification unchanged.