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Creative Weighting allows you to determine how much of your budget goes to each creative associated with a line item. For example, if you know creative A is more effective than creative B, you can set up creative weighting so that creative A serves twice as much as creative B.

Note: You cannot weight across creatives with different sizes or placement types.

To set up creative weighting

1. Select “+ New” button> “Line Item” to set up a new line item or select the pencil icon to the right of a line item to open the edit view
2. Select ‘Weighted’ from the ‘Creative Weighting Method’ dropdown in the line item overview. 

1. Associate creatives with the line item, and assign a value between 1 and 100 for each creative to determine the relative weight with which it will serve. The weights will serve in ratio to each other. For example if you give creative "A" a weight of 2 and creative "B" a weight of 1, "A" will serve twice as often as "B" (2:1). 
   
2. Select Save & Close. 

FAQs

Q: Are weights passed to custom bidding agents?
A: No, weights are not passed to custom bidding agents. However, as part of this release, we are changing the way our bidder handles custom bidding agent responses. Currently, when a bidding agent does not return a creative_id with a bid, the bid is dropped. With this change:

• If the bidding agent returns a creative_id, that creative will be used
• If the bidding agent returns no creative_id, we will choose a creative randomly regardless of the creative_weighting_method

Q: Will the creatives deliver exactly to the weightings provided? / What happens if impressions in reporting do not match the weightings provided?
A: The weights are applied after all targeting and creative eligibility is matched. It is possible that a set of creatives may have different abilities to match auctions prior to the weighting, causing the final impression ratio to differ from what was expected. For example, if two identical creatives were weighted 1:1 but one of the creatives had a declared advertiser that was blocked by some auctions, that creative would, in fact, serve less than evenly

Q: Can creatives be weighted to click through or other performance metrics?
A: This is not currently supported, but may be in the future. 

Q: My creatives do not appear to be delivering according to their weights. Why?
A: There are several reasons why the number of impressions you see in reporting may not match the weighting ratios set on a line item:

• Weights are calculated randomly for each bid without any sense of "history".  Over time, this should even out but line items with very small budgets may not conform to the weighting ratios.
• Because weights are applied to bids and not impressions, it is possible that one creative will win more simply by chance.  Again, this is more likely to impact line items with small budgets.
• In order for the weighting to be applied, creative attributes must match exactly.  Beyond creative size, differences in other attributes such as MRAID/non-MRAID, Javascript/Image could cause deviations from the desired weights.