Yes. There's nothing new about this, I can barely comment on any thread without mentioning it, and I got the idea here from other publishers years ago. It has always worked out for us that not running Adsense on pages that don't convert well results in increased earnings for our site. In our case, we just target an eCPM of $XX.XX for every page, and those that don't make the grade over time go ad-less.
Out of laziness and workload, I didn't follow that course of action this summer and our earnings were down, year over year, for the first time. I used the excuse that I wanted to see how Google would manage the site without "interference" from me, I'll be smarter next year. As is, we run Adsense on less than 25% of our page views. Putting more pages into the mix with lower eCPMs always results in quick loss of overall revenue. The only thing I'm not really confident about is whether it's the low eCPM or the low conversion (the two are usually but not always coupled) that hurts. I'm beginning to suspect it may be the low conversion.