The account_id of the publisher (aka site) to which the bid modifier should be applied.
For a list of all publishers on a given admin network, use the publishers endpoint. (Refer to the account_id field returned.) Speak to your account manager to obtain the list of admin networks that are applicable for your campaigns.
For a list of publishers (sites) on which your campaigns have previously run, use the Campaign Summary Report, with the site_breakdown dimension. Refer to the site field in that report. (The site field is the publisher account_id.)
Must be between values 0.011 - 2.0
(CPC boost must be between -99% and 100%)
Min/Max cpc_modification values:
0.011 - apply a boost of -99% (Min)
2.0 - apply a boost of +100% (Max)
Campaign-level cpc = 0.8
To apply a boost of -50% for demo-site-1, set its cpc_modification to 0.5:
site-specific bid = 0.8 x 0.5 = 0.4
To apply a new boost of -12.5%, set it's cpc_modification to 0.875:
site-specific bid = 0.8 x 0.875 = 0.7
To apply a new boost of +12.5%, set it's cpc_modification to 1.125:
site-specific bid = 0.8 x 1.125= 0.9
At all times, the campaign-level cpc remains unchanged (0.8)
cpc_modification is publisher-specific and has no effect on the campaign-levelcpc.
Modifiers are not accumulative. The modifier most recently submitted for that publisher is applied against the campaign-levelcpc.