Are you sure your CPM is $151.84? That seems rather high... maybe you're looking at your estimated earnings?
Anyways though, about CPMs, here's an extract from our FAQ, hope it helps!
First of all, what's "CPM"?
CPM stands for Cost Per Mille, or Cost Per Thousand. It's the amount of money that an advertiser pays per 1000 views of his ad. Off this CPM, YouTube takes a portion (roughly 45%) for themselves. We're left with what is called the RPM, or Revenue Per Thousand.
This is how much money the channel is earning. Your network takes a percentage of the revenue in exchange for its array of services.
Got it? Great!
What defines my CPM?
There are a few different factors that are taken into consideration when defining the CPM:
- Channel Audience
- Channel Content
- The Economy
- Seasonal Trends
Let's explain each of these things one by one:
Channel Audience
Advertisers have a target audience when they place an ad. Let's take an example: If Sony wants to run a campaign to promote their PlayStation 4, they might be targeting Men in Europe & North America, ages 18-25. If your channel's demographics fall into this category, your channel will display PlayStation ads. Another part of your channel taken into consideration under this category is your viewership. Larger channels (with the same viewer demographics) will always have higher ad revenues because the viewers have a bigger chance of watching the ad longer (if it's a pre-roll ad).
Channel Content
Let's grab our PlayStation example once again. Sony is also going to want to target their ads to gaming channels, rather then say, fitness channels (yes those do exist). Therefore, CPMs for gaming channels will grow when a major gaming-related ad campaign is going on. Seeing as most of our partners are gamers, it's fair to say that if the gaming industry was to weaken, ad revenue would decrease.
The Economy
This one's easy to understand: advertising is influenced by the amount of money that's put into it, so less money means less revenue on your channel. Simple as that.
Seasonal Trends
This one may be the most important of all 4, because it's the one that influences CPMs most.
During mass shopping periods of the year such as Christmas, September (Back to School shopping), and Summertime, CPMs can be up to 5 times higher than during the slower months (January, February). This is due to advertisers wanting to promote their products as much as possible during these periods of increased spending. Unfortunately, after seeing high CPMs for a certain amount of time, you'll see that they can abruptly go down once the sprees are over. This is typically seen in January and February of every year, just after Christmas (biggest advertising period of the year). It is not uncommon to see a December CPM of 15$ drop to 4$ in January for example.
You can always check your current CPM on YouTube Analytics (Ad Performance), if you're a member of a network that is transparent about that.