Can Adwords campaigns affect other campaigns performance?

[peigenesis]

I understand that keywords and adgroups within a campaign can affect the performance of other keywords within that parent campaign.

I was interested to understand whether campaigns in my account can affect one another.

I have an adwords account with around 30 campaigns. Some are heavy hitters and others get minimal to 0 traffic. Will these low quality campaigns drive up the costs of my high end campaigns?

[mjtaylor]

Without addressing your specifics, I can guess yes based on my experience with campaigns in one of my client's Adwords account. In talking with an adwords rep about an issue with one campaign, he repeatedly referred to the influence of a separate campaign within the same account.

May I suggest you call an Adwords rep yourself and inquire directly about the problem?