EPC refers to the earnings generated per 100 clicks.

Bearing this in mind, the two main reasons for EPC variation are traffic and offers.

First of all, traffic quality is a great factor since it's always changing.

This means you can't control the performance of the users you're driving to the offers.

If you work with an ad network, you've got the rankings that'll allow you to control the traffic quality.

However, there isn't much you can do on other sources.

The performance of the offers can fluctuate if there's a carrier/advertiser problem.

Apart from these issues, offers tend to be stable.

Moreover, you need to know whether or not you've got a good offer, in general terms.

For example, a nice mix of great payout and an easy subscription flow such as Single-Optin will do the trick!

You can improve your EPC by optimizing your traffic.

Check your stats thoroughly and focus only on the best segments!