I recently had the opportunity to catch up with Kirby Winfield, the SVP of corporate development at comScore, Inc., and ask him a few questions about consumer data and data in general. Tim Nichols: What is the biggest mistake marketers make when purchasing and applying consumer data products? Kirby Winfield: Not going in with a clear sense of what they're trying to measure, and why. It's easy to get lost in all the data when you don't go into it with an understanding of what your marketing objective is. For example, are you trying to optimize your TRP, or are you trying to lower your cost per lead? The same data can be applied in very different fashion to achieve those distinct objectives. When you have a clear sense…