Reporting discrepancies are common and expected when multiple
systems are used to measure line item delivery. If you want to investigate a
reporting discrepancy, use the resources below for assistance. It's best to investigate
discrepancies while a line item is still running, since there are fewer
troubleshooting steps available after a campaign has ended.
Third-party discrepancies
When an ad server delivers line items
that are hosted by a third party, reporting discrepancies between the two
systems will occur, and it is common to see campaign variances of up to 20%.
Check the lists in "More about third-party discrepancies," below, to
learn why discrepancies may occur and what you can do to prevent them.
Discrepancies may
result from:
Latency: Lag
between an initial line item request and the appearance of the creative can
lead to differences in counts. For instance, a user will often navigate away
after the browser receives the DFP line item request but before the third party
responds with the requested line item, or a user may click on a link but
navigate elsewhere before the landing page has loaded.
Network connection
and server reliability: A third-party ad server may fail briefly or
encounter an issue that prevents it from logging an impression.
Ad blockers: Ad
blocking software can prevent the line item from being delivered by the third
party after DFP has already counted an impression.
Low impression goals:
A small numerical discrepancy can cause a high percentage discrepancy if the
line item delivered few total impressions. For example, if you have a campaign
delivering 100 impressions per day, a single-day discrepancy of 30 impressions
will lead to a single-day discrepancy of 30% even though the actual number of missed
impressions is low.
Tracking
methodologies: DFP counts line items requests, but a third party may record
an impression at a different time (e.g., when a tracking pixel is rendered).
Filtering: Ad
servers have different methods for filtering impressions from spammers, bots,
spiders, back-to-back clicks, link analyzers, and other automated or
non-representative web traffic.
Things to check:
1. Are macros implemented properly?
2. If DFP recognizes the third-party ad server you are using,
let it automatically insert the macros. If you are unsure of where to place
macros, talk to your creative developer, advertiser, or third party for
guidance.
3. %%CACHEBUSTER%% -- Make sure there's a random number
properly inserted in each call.
4. %%CLICK_URL_ESC_ESC%% or %%CLICK_URL_UNESC%% -- Verify that
the click macro is included in the correct portion of the click-through URL in
your code.
5. %%VIEW_URL_ESC%% or %%VIEW_URL_UNESC%% -- For interstitial
creatives, ensure that this macro is included in your creative's code.
6. As a best practice, we recommend using an unescaped
(...UNESC) click macro when the creative hosted by another server is a standard
image file such as a GIF or JPEG. You should use the double-escaped
(...ESC_ESC) click macro for Flash creatives and certain third parties.
7. If you are using Google Publisher Tags (GPT), have you
defined more ad tags in the webpage header than you display in the body section
of your webpage? Ad tags that are defined in the header but not displayed in
the body will be counted as impressions whenever the tag is loaded, but they
won't make calls to third-party servers. That will lead to discrepancies. Make
sure that all ad tags defined in the header are also displayed in the body of
the webpage.
8. Are you comparing the same date range across the third party
and publisher?
Do both DFP and the third party use the same time zone? Ad
servers that report based on different time zones will return different
results.
9. Are you comparing the same line items/ads?
10. Do you use the same third-party tags in any other line items
in your network?
11. Did you confirm with the third party that the same tags have
not been provided to any other publishers?
12. How large is the creative asset? Large creatives can have
long load times and can cause differences in impression count timing.
13. Does the DFP report include unfilled impressions? Unfilled
impressions will inflate DFP’s numbers by including instances where the
third-party ad server was not called.
14. Is the line item using geographic targeting on the
third-party ad server? Different ad servers map IP address location data
differently, leading to significant discrepancies.
Is the line item day- or time-parted on the third-party ad
server? Day- or time-parting on the third-party ad server can lead to DFP
counting impressions in situations where the third party does not return a line
item.
15. Does the creative require calls to multiple third-party ad
servers (also known as "daisy-chaining")? Each third-party ad server
can lead to campaign variances of up to 20%. If one third-party server points
to yet another third-party server, the expected discrepancy increases. (With
80% accuracy between each server, this results in a normal discrepancy of up to
36%, as shown in the following calculation: 1 - (1 - 0.2) × (1 - 0.2) = 0.36).
16. Does the third-party ad server use frequency capping? A
third-party frequency cap will prevent an ad request from being filled despite
the fact that DFP has counted an impression.
Source: Google support
