There are several different ways to organize the ad tags on your website. In this post, we look at some of the common strategies and discuss pros and cons. All of these methods work! In truth, it’s a matter of preference.

Throughout this post, we will be referring to the following layout, which has one 728×90 ad unit and two 300×250 ad units.


Our preferred method is to create a new ad unit for each ad slot on the page. For our example, that would mean 3 new ad units, each with a specific size:

  • ROS_728x90
  • ROS_300x250_ATF
  • ROS_300x250_BTF

ROS is an acronym meaning either “Run of Site” or “Rest of Site”, depending on context and who you ask. Either way, it refers to an ad unit that is not specifically something else (ex. a homepage-only unit).

What are the advantages of this method? Targeting is easy. You will target each line item to a specific ad unit. DFP’s reporting works especially well with this method.

What are the disadvantages? Mostly, it is extra work. You may end up with a lot of ad units and you will need a knowledgeable web developer to make sure that the right ad units appear on each page.

A different strategy is to repeat the same unit multiple times, and then use Custom Criteria (that is, key-value pairs) to target individual units as necessary. This approach seems very popular with DFP Premium. In our example, you would have only one ad unit and it would work for all sizes:

  • ROS

However, you would use setTargeting to target each of the 3 units. For example:

  • setTargeting(‘placement’, ‘leaderboard’)
  • setTargeting(‘placement’, ‘medrec-atf’)
  • setTargeting(‘placement’, ‘medrec-btf’)

This method works. You will be able to target your line items to specific ad units by using Custom Criteria.

The main advantage is simplicity, particularly when working with multiple sizes. You don’t have to think too hard about what is targeted where. Just add another line item and target to the main ad unit and it will run wherever the size matches up. This setup may be a bit easier for web developers to work with as well.

The big downside is reporting. Certain reporting dimensions in DFP are only available at the ad-unit level. By combining everything into a single ad unit, you lose some interesting reporting capabilities. For example, you cannot easily run a report on ‘Unfilled Impressions’ to figure out if a particular ad unit is showing blanks. It may be possible to tease this information out of another report, but why make it difficult? The same goes for viewable impressions.

Other considerations

If you are running multiple website from a single instance of DFP Small Business, you should definitely prefix your ad units with the site name or an acronym. If you have DFP Premium, you can use an ad unit hierarchy here instead. Please don’t run the same units on multiple sites! You’ll be sorry when it comes to do reporting.



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