How do you deal with keywords for which the ROI fluctuates?

I can't figure out the best way to manage this

[limitup]

Lately I have a really annoying problem - high volume keywords where my ROI is fluctuating quite a bit. I've never had this problem with these keywords before, but try as I might I can't figure out why this is happening now.

My dilemma is how to manage these. There are too many to manually review every few days, or weekly. Although I guess I could develop a system using their API to do it programmatically.

Even if I did this I can't figure out what I would do to manage them effectively. If a keyword wasn't performing well for the past week and I turn it off, then what ... I'll never know when to turn it back on.

These are high volume keywords where I get 100-500 clicks a day, and my lifetime ROI is around 100%. For the past month or so my ROI has been fluctuating dramatically. One week it will be 100%, the next week 12%, the next week 120%, etc.

In all my years of using AdWords and probably spending a million dollars with them, I have never had this problem.

Help!

[JBrown]

Maybe average what you need/want to get over a longer period of time.

Week 1 ROI: 100%
Week 2 ROI: 15%
Week 3 ROI: 75%
Week 4 ROI: 5%

Rough monthly ROI: 24%

If that works for your goals, then don't worry as much about weekly fluctuations.