10. They can't do the math
Just because you can measure a banner clickthrough does not mean it has any more relevance to moving your business metrics.
The thing that makes the internet so special as an advertising tool is the ability for the advertiser to know exactly how effective their ads are and to then make inexpensive changes on the fly.
How does your interactive agency take the data and translate it into actionable ideas to improve your media mix or creative messaging? From ad and creative optimization tools for display advertising to auto-bid-management tools for SEM, to segmentation analysis, ROI and LTV calculations, make sure your agency has the media talent in place not only to know the right tools but to assess the results based on your business metrics.
Things to consider
Often, things are measured in interactive because they can be measured. No one ever asked the clickthrough rate on an outdoor billboard because you can't measure that. Just because you can measure a banner clickthrough does not mean it has any more relevance to moving your business metrics.
Make sure your agency in tying performance back to your business, not to the things the tool measures. I am often amazed at the number of times I hear someone say, "I've improved the clickthrough rate on the creative 25 percent!"
But what does that mean?
Always ask what it means, and make sure your agency asks, too.
Next: Conclusion