Click Through Rates in Adsense can be a handy way of predicting your future Adsense Income and build growth for your site. At present mine is currently running at around 5% for the last 12 months. Now the industry average for direct mail response is 5% which seems about right. So based on this I can start to plan future earings around my site. For example If i add another 50 articles that I can be confident of that staying around that figure and work out whether it is cost effective to continue with my site, in my instance it is. What sorts of click through rates are DP members getting and what would you expect your site to be hitting?
avg CPC and your historical traffic data would be a better indicator of future growth. But the financial climate has made it hard to predict anything. Your CPC could be one thing today or slashed in half tomorrow.
If there is one thing I've learned is that Adsense is unpredictable. CTR goes up, hmmm, funny, my ePC seems to have gone down. Impressions go up, hmmmm, my CTR just went down. My impressions went down, hmmm, my CTR is also going down...hmmmm, wow, look at how high my ePC is!