Because search and content network statistics can differ greatly, viewing aggregate statistics for a campaign running on both networks may not give you granular insight into your performance. To provide better insight, Google has made a small change to the campaign and ad group summary pages that allows you to easily evaluate search and content network statistics separately. The new "Statistics" drop-down menu lets you change your view to see search and content network statistics in individual rows for each of your campaigns and/or ad groups. You can also filter to see only the statistics for the network you choose. By separating the statistics by network on your summary pages, you can not only see which campaigns or ad groups need your attention, but you can also identify which network you need to optimize for. Optimization strategies for the search network are often different from strategies for the content network.
When comparing your performance on search and content networks, look at your cost/conversion (measurable through AdWords conversion tracking). This metric is very useful since your target cost/conversion is likely to be the same for both networks and can be used as an accurate measurement of your overall ROI.