What is eCPA in online affiliate marketing?

In order to explain what dCPM is easily, we need to introduce the term eCPA – effective cost per action. We add an action count (Lead for instance) to the previous examples, and calculate how much did the advertiser actually paid for each Lead act. Lets assume the advertiser is protable when he pays 5$ per lead.
eCPA on a CPL/CPA/CPS model
Here naturally, the eCPA is the predened CPL.

Although the cost per Lead was as desired by the advertiser, the publisher might drop the campaign receiving only $0.3 eCPM on day 3.
eCPA on a CPM Model
In this case, the eCPA reects the total cost each day divided by the number of leads. We can see that the advertiser has very little control regarding the price he pays for each lead.

Here, the publisher might be satised with his 0.5$ CPM but the advertiser loses on day 1 and day 3 paying more than 5$ per lead dropping the campaign as well.
eCPA on a CPC Model
Similar to the CPM model, the eCPA reects the total cost each day divided by the number of leads. Although sometimes there is some correlation between the number of clicks and the number of acquisitions, still the advertiser has little control over the price he pays for each lead.

Although the publisher in this example receives satisfactory eCPMs, the advertiser is not protable at $8 per lead.