Why does eCPM fluctuate?

Discussion in 'iOS Programming' started by ArtOfWarfare, Sep 22, 2011.

  1. ArtOfWarfare macrumors 604

    ArtOfWarfare

    Joined:
    Nov 26, 2007
    #1
    Why does eCPM fluctuate and how can I raise it up?

    The first day my ad supported app was on sale, it only made 21 impressions, but had an eCPM of $9.26, and so I made $0.20. Not good, really, but at least it was something (more than my $0.99 app which gets about one sale per week.)

    The next day, I had 60 impressions, but the eCPM had dropped to just $0.70, so rather than make $0.60, I made just $0.04! Seriously? Impressions were 3x as much as before, but the eCPM was less than 1/10 of before so I made a lot less revenue.

    This is just small change right now, but I'm hoping as I start getting more reviews out for my app the number of impressions will begin being in the thousands instead, but if the eCPM is so low, then it's going to be impossible to make any money off of this, so I need to know: why does eCPM fluctuate and how can I raise it back up to the nearly $10 it was on the first day?

    (Today is the third day and the eCPM is back up to $1.40, so a lot better than yesterday, but no where near as good as the first day.)
     
  2. dejo Moderator

    dejo

    Staff Member

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    The Centennial State
    #2
    eCPM fluctuates because revenues and impressions fluctuate. Do you understand how eCPM is calculated?
     
  3. ArtOfWarfare thread starter macrumors 604

    ArtOfWarfare

    Joined:
    Nov 26, 2007
    #3
    The definition is round about. eCPM varies with revenue and revenue varies with eCPM. It makes no sense. I want to know how it's possible for me to end up having 3x as many impressions on one day as another, yet have 1/5th as much revenue.
     
  4. dejo, Sep 22, 2011
    Last edited: Sep 22, 2011

    dejo Moderator

    dejo

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    #4
    The definition is pretty clear cut, actually:

    eCPM = (revenue ÷ impressions) x 1000​

    Revenue is pretty much a black box, and dependent on numerous factors. Suffice it to say, whatever revenue Apple gets from you serving ads, they pass 60% on to you, assuming you are using iAds.
     
  5. ArtOfWarfare thread starter macrumors 604

    ArtOfWarfare

    Joined:
    Nov 26, 2007
    #5
    Yes, and revenue is equal to

    Revenue = (eCPM x impressions / 1000)​

    These are round about definitions. Revenue is the number coming out, so I put it by itself on the other side. Impressions is straight forward... it's when my app attempts to get an iAd to display, and successfully gets one. eCPM, however, I don't understand at all. It seems to be a random number. I almost feel like Apple is just lying about what the eCPM is, so that they can hold onto all the money they get from the companies that make iAds and screw me out of my cut of the money.
     
  6. dejo Moderator

    dejo

    Staff Member

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    Location:
    The Centennial State
    #6
    Fine, argue with me. Revenue is the 60% amount that Apple has committed to pay you. It's an "input" value, determined by another system. eCPM is just a guidance calculation that you can use to determine the effectiveness of your advertising.

    eCPM is not random. It's calculated using that formula.

    How do you think they got such a cash hoard? ;)
     

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