Floodlight only records conversions for users who have previously seen or clicked on a Campaign Manager ad within a period of time that you specify, called a lookback window. When a user loads a webpage containing Floodlight tags, the ad server accesses the user's Doubleclick cookie. Campaign Manager then runs an overnight process for each Floodlight impression, checking to see whether the ID is a match for any previous impressions or clicks on Campaign Manager ads within the lookback window. If no match for the cookie ID is found, the record of the activity is discarded.
Lookback windows are determined by your Campaign Manager account's report publish time setting (except in the case of reach, frequency, and P2C reports, which are given in EST). They are measured by calendar days, not hours. For example, if an activity occurs on Tuesday evening, then any impression from Monday falls within a 1-day lookback window, even if it occurred more than 24 hours prior to the activity. It counts as "one day ago." A quick way to remember this: your lookback window always extends back to 12:00AM of the earliest possible calendar day. Let's apply this rule to our original example: if an activity occurs at 7:30PM Tuesday, then a 1-day lookback window spans from 7:30PM Tuesday to 12:00AM on Monday. Likewise, a 3-day window would span from 7:30PM Tuesday to 12:00AM Saturday. In P2C reports, a window size of 1 means 48 hours and a window size of 2 means 72 hours.
The lookback window for any given user impression or click is based on the value set for the placement where it took place. If a user has clicked or viewed ads in multiple placements, Campaign Manager uses the most recent click that falls within the lookback window of the placement where the ad was served. If no click is available, the most recent impression is used.
Bob's Widgets is running a campaign across Placement A and Placement B. A user sees the ad called "Love the Lemur" in Placement A. A few minutes later, the user sees the ad called "Pet the Panda" in Placement B and decides to click because pandas are adorable. Ten days later, the user visits the advertiser's site and makes a purchase, triggering a Floodlight impression for a sales activity.
Placement A's lookback window for impressions is 14 days. Placement B's lookback windows for clicks is 5 days, so the click can't be used for calculating Floodlight data. However, Placement B's lookback window for impressions is 14 days. As such, Floodlight records the impression as a sales activity and associates it with the impression of the ad "Pet the Panda" served to Placement B.
Note that for publisher tags, the lookback windows for the advertiser are used, not the lookback windows for the placement. To avoid discrepancies, we recommend that you set lookback windows at the advertiser level and use default values for placements.
If you share your Floodlight configuration across Campaign Manager and Search Ads 360 and update your lookback window in Campaign Manager, that update will propagate to Search Ads 360 and will be used going forward.
Lookback window settings
Lookback windows can be set for an account, advertisers, campaigns, placements, and sites. The maximum lookback window is 90 days.
Lookback windows without overrides
Lookback windows are simplest if you don't set any overrides at the campaign or placement levels. An override is a lookback window setting that supercedes the inherited value.
If you don't use overrides, you only need to set lookback windows at the account and advertiser levels. Advertiser values are used in placements. If you change an advertiser's lookback windows, these changes are reflected in placements.Learn about overrides
Lookback window overrides can be set at for placements and campaigns. An override value can't be greater than the value set for the advertiser. For example, if the lookback window for clicks is 10 days for the advertiser, you can create a placement override of 7 days, but not a placement override of 14 days.
When you set an override in a placement, the placement's value is saved, regardless of changes at any other level. There's no way to make batch changes to placement lookback windows that use overrides.
If you remove the overrides from the placement, it will revert to inheriting the advertiser's lookback windows, and subsequent changes to the advertiser's values will be inherited by the placement.
Campaign overrides are used to set the lookback windows for new placements that you create manually in Campaign Manager.
When a new placement is created, the campaign override values are used to set default values as overrides. Because the placement is thus using overrides, subsequent changes to the campaign values won't be inherited by existing placements.
Site lookback windows
You can set lookback windows for sites. If no campaign override is set, the site lookback window is shown as the value when you're creating a new placement. To use the site value in the placement, you must enable an override. Otherwise, when you save the placement, it will revert to inheriting the lookback window from the advertiser.
Because site lookback windows are difficult to apply, it's generally best not to set lookback windows at the site level.
All of these inheritance rules apply separately for each lookback window. For example, a placement could have an override set for its lookback window for clicks, but not for impressions or Rich Media events. Similarly, you can set a value for some but not all types at the site level, and you can set overrides for some but not all types at the campaign level.
Lookback windows and publisher tags
Floodlight uses advertiser lookback windows, not placement lookback windows, to decide whether to serve publisher tags. That means that if you've got lookback window overrides in a placement, you might serve the publisher tags more often than you count a conversion.
For example, the lookback window for clicks is 10 days at the advertiser level, but 3 days at the placement level. A user clicks on an ad on Site A, then visits a Floodlight-tagged webpage 5 days later. No conversion is counted because it's outside the lookback window for the placement. However, Campaign Manager serves the publisher tags for Site A based on the advertiser lookback window.
This discrepancy is particularly significant if you use publisher tags to serve tracking tags for your sites, because it could lead to a disagreement over the number of conversions the site has provided.
This is only an issue if you use overrides in your placement lookback windows. To avoid this problem, don't use overrides.
Effects of changing placement lookback windows
You can change lookback windows to make them longer or shorter. When you do, the changes are immediate and are applied to any new Floodlight impressions. However, Floodlight impressions from before you made the change are not reprocessed. In other words, changing your lookback windows doesn't change the number of conversions that were counted prior to the change. It only affects how conversions are counted from that point on.
Example: Expanding lookback windows
You have a placement with an impression lookback window of 5 days. Six days ago, a user saw one of your ads. Today that user visited your Floodlight-enabled webpage. A Floodlight impression is recorded, but it's not a conversion because it's outside the lookback window.
Subsequently, you change the impression lookback window to 10 days. This change has no effect on the Floodlight impression that already occurred. The next day, however, the user returns to your webpage, triggering another Floodlight impression. Seven days have now passed since the user saw your ad. Since the impression lookback window is now 10 days, a conversion is counted.
Example: Shortening lookback windows
You have a placement with a lookback window of 10 days for impressions. Four days ago, a user saw your ad. Today that user visited your Floodlight-enabled webpage, and a conversion was counted.
Subsequently, you change the impression lookback window to 3 days. This change has no effect on the conversion that was already counted. However, when the user returns to your webpage the next day, no conversion is counted because the lookback window is now shorter.