It can be really frustrating to see your traffic spike and then also see RPM head in the opposite direction.
This happens for many reasons, so let's look at what those may be, and learn how to figure out what's going on with your own traffic and RPM.
To understand why RPM dips, first let's look at what RPM is.
Revenue / Traffic * 1000 = RPM
RPM is just this equation. It's not the rate at which you are earning (a common misconception), but rather a way to measure your revenue relative to your traffic. When RPM drops or increases, it does not mean you earned less or earned more.
It does mean that traffic is monetizing at a different rate per 1000 sessions or pageviews. RPM is meant to be used as a guide. A low or high point indicates that you need to look at the specifics of both revenue and traffic.
First Look at Revenue
Look at the Earnings graph in your Mediavine dashboard.
Did earnings increase with traffic? If so, that's a good sign and you can skip down to learn more about traffic and how advertisers plan budgets.
Did earnings stay flat or decrease while traffic increased? If that's the case you might have a bigger issue. Check out this article on the steps to troubleshoot that.
Next Look at Traffic
Not all traffic is created equal. Different kinds of traffic will monetize at different rates. Variables can include sources (Google, Pinterest, Facebook, etc), countries of origin, or the posts / pages on your site that are seeing the traffic.
HERE'S HOW TO NARROW IT DOWN
Adjust the date range in your dashboard to look at JUST the traffic spike.
Compare to the same days of the week in the week prior. This will allow you to see the differences.
Look at devices. An increase in mobile traffic can be the reason for serving fewer impressions or lower CPMs.
Look at the Traffic Source report. An increase in a particular source of traffic might yield lower impressions or CPMs. If you see an increase in a traffic source, look at the CPMs of that newly increased source compared to what was higher in the previous week.
Look at the By Country report. U.S. traffic always has the highest CPMs, so a decrease in US traffic can impact revenue which impacts RPM. An increase in traffic from countries that do not monetize with high CPMs (India, Thailand, Brazil, etc...) can also negatively impact revenue which pulls down RPM.
Look at the Ad Unit report. Are impressions low relative to the increase in traffic? If so, do the traffic sources or countries point to why?
Look at Page Level Data. Trending content can also contribute to a drop in RPM when traffic spikes. If the post or page receiving an influx in traffic is short, or not serving the same number of ads as other content, OR if you have an increase in traffic to content that is not brand safe, that might be the reason. Open the trending post(s) in an incognito window and be sure to look at them on mobile.
Click any jump links that are obvious to a reader and see where you land. Look for pop-ups or other elements that might be interrupting user experience.
Add ?test=placeholders to the end of the URL and make sure that you have an appropriate number of ad slots. Here's how to count your ads.
Check Google Analytics
Make sure your analytics connection is good. Doubled analytics is a very common reason that page RPM looks low (because you are effectively dividing revenue by twice the traffic). Accidentally disconnecting analytics or installing it incorrectly can make RPM look artificially high.
Make sure that the Google analytics profile connected to your Mediavine dashboard is set to New York time zone. Advertiser reporting is set to New York, so if your analytics are set to a different time zone, revenue and traffic reports won't line up which will skew RPM, especially if you have a spike in traffic.
See this article for instructions on updating your Google Analytics profile to the correct time zone.
Understand How Advertisers Plan Budgets and Spend
Advertisers typically plan how they are going to spend in advance. It's the reason late November and early December budgets are predictably high, and early January and July are predictably low. Planning ahead also applies to day to day spend. That's how we are able to project the best days of the year.
Advertisers typically commit themselves to buying a particular amount of premium campaigns on any given site in a day. When traffic spikes, they tend to burn through those premium campaigns more quickly -- because there's more traffic than they'd planned for.
Kraft (the advertiser) has 10,000 impressions that they need out there today, and no matter what, they're willing to pay well for it. Each of your ad spaces is an auction, and Kraft will spend top dollar to win the auction for those 10,000 impressions
But after those 10,000, Kraft might be done for the day, or they might want to serve more, but they're not as desperate to have them filled, so they're not willing to pay as much.
Programmatic advertising means there's always inventory available. But the CPM becomes very dependent on how much advertisers want to be in front of your audience. Since we make them bid against each other, they have to prioritize how and where to spend money, and if they've already decided what they're spending on a particular day when you're seeing a surge, they may not pick up the slack the way you'd expect them to.
The Good News
If your traffic spike is sustained, advertisers will adjust after a couple of days and they will increase the budget allocated to meet your new higher demand.