Today we’re launching the Ad Exchange Real-Time Bidding Optimization Series on the developer's blog to share updates, best practices and optimization tips with AdX developers. Our goal is to provide knowledge to our clients to help keep their proprietary bidders healthy, successful and evolving. To start things off the first blog post in the series covers post-filtered bids.
When using Ad Exchange, one of the most important factors is ensuring that your bid response is participating in the auction. If the bid response makes it to the auction, it has a better chance at improving win rate: percent of impressions won out of all bids submitted. However, it’s possible that some of your bids may not be entering the auction due to bid response filtering.
We’ll review bid response filters later in this blog entry: what they are, and how to ensure your bid responses are not filtered out. But before we dive in, let’s define bid response filtering.
What is bid response filtering?
Each real-time bid that is submitted to Ad Exchange undergoes a screening process before it can enter the live auction. During this process, your bid may be filtered due to publisher exclusions or incorrect use of the RTB BidResponse protocol. Among other things, we check for malformed URLs, ads that fall into a category the publisher has blocked, or incompatible elements in the bid response (e.g., a buyer who has declared an expandable ads technology vendor, but who has not actually trafficked an expandable ad).
Here is a basic visual representation of the process a bid goes through, including bid response filtering, to make it into the auction and win:
What are the main bid response filters?
As the bid response progresses through the process illustrated above, it might be filtered out by Google, the publisher, or during the actual auction for many different reasons. Each of the main bid response filtering mechanisms are discussed in detail below.
Google Filtered: First, Google will review the bid response to determine if both the ad creative and bid are compliant with Google’s policies and standards. Here are the most common reasons your bid response will be filtered out by Google:
Disapproved ad means that the ad in the bid response was disapproved due to one of several reasons. In order to determine the exact reason for which your ad was disapproved, review your
snippet status report. The
snippet-status-report-proto.txt file lists all the issues described in the <DisapprovalReason> section of the report.
This is usually the culprit when your bid has been filtered out!
Note: The
snippet status report will also show ads that have not been checked and are filtered.
And as a proactive measure, the
creative REST API provides methods for submitting a creative for verification, for checking the status of a creative that you have submitted, and for retrieving a list of all your active creatives before bidding on the creative ad.
Max CPM is 0 or negative means the bid (max_cpm_micros) set in the bid response was 0 or a negative value. Change the bid to a positive value. If you are not interested in bidding for a particular bid request, be sure to return an empty bid response with the processing time set, not just an empty (0 bytes) response.
Click through URL is too short means for bid responses where html_snippet is set, the click_through_url is less than eleven characters. For example, the URL http://a.b would be too short. Verify that your click_through_url is more than eleven characters.
Click through URL is unparsable means the click_through_url in the bid response is malformed and cannot be parsed. For example, 'http://myad' will not work, since the domain name has to include at least one '.' (period).
Incorrect use of bid response protocol means that there is an improper setting in the BidResponse. In order to determine the proper protocol, review
Building the Response and the
realtime-bidding.proto.txt file. The
realtime-bidding.proto.txt file defines the appropriate settings that should be included in the BidResponse. Examples of incorrect protocol use include: buyer_creative_id not set in the BidResponse or setting both the html_snippet and video_url fields in the BidResponse (only one should be set).
Poor landing page quality means that the landing page was disapproved by Google. Review the landing page of the ad to make sure the website provides a good
user experience as measured by:
- Relevant and original content: The site needs to be relevant and have original content, it should not copy text from another site.
- Transparency: The site needs to be very clear on what the business model is and what the information will be used for.
- Ease of navigation: The site should be easy to navigate and it should not be intrusive to users.
Publisher Filtered: Once the bid makes it through Google’s review, it is reviewed again to ensure it adheres to the publisher’s requirements. For each piece of ad inventory, the publisher can add exclusions. Here is a list of the main reasons a bid could be filtered by a publisher:
Sensitive category URL excluded means that the
click_through_url in your bid response was either detected or declared with a sensitive category which was excluded by the publisher for this request. In order to determine the sensitive categories for each publisher, you will need to review the excluded_sensitive_category field in the bid request and the
publisher settings report. The
publisher-settings-proto.txt file lists the categories that are excluded. Your
snippet status report will show the sensitive category with which your snippet’s click_through_url was classified by Google.
Product category URL excluded means that the click_through_url in your bid response was either detected or declared with a product category that has been excluded by the publisher for this request. In order to determine the product categories prohibited by each publisher, review the excluded_product_category field in the bid request and the
publisher settings report. The
publisher-settings-proto.txt file lists the categories that are excluded. Your snippet status report will show the product category with which your snippet’s click_through_url was classified by Google.
Declared vendors excluded means the bid response has declared a vendor_type which has been excluded by the publisher’s ad slot in the bid request. In order to determine the vendor types allowed by each publisher, review the allowed_vendor_type field in the bid request and the
publisher settings report. The
publisher-settings-proto.txt file will show you the allowed vendors.
Declared attributes excluded means the bid response has declared attributes which were excluded by the publisher’s ad slot in the bid request. In order to determine the allowed_vendor_type per publisher, you will need to review the excluded_attribute field in the bid request and the
publisher settings report. The
publisher-settings-proto.txt file will list the excluded attributes.
Auction Filtered: After the bid response passes the Google and publisher reviews, it makes its way to the auction. However, the bid may not enter the auction if it was lower than the publisher’s required min CPM. If this is the case, a ‘Max CPM is lower than the publisher’s min CPM’ message will be generated.
Max CPM is lower than the publisher’s min CPM means the bid response contained a max_cpm_micros value that was less than the publisher’s min_cpm_micros setting. Ensure your bidder reviews the min_cpm_micros required by the publisher per bid request in order to bid properly on the impression. The min_cpm_micros value is listed in the AdSlot section of the bid request, you can review more details in the
realtime-bidding-proto.txt file.
Have questions or want to get a report for your bid response filtering issues? Reach out to your Ad Exchange account team.
Posted by the Ad Exchange Team
