My Mobile RPM is about 60% of desktop. I think it's always going to be lower for me just due to site layout.

My mobile RPM (over the past five million impressions or so) is about half of desktop; my tablet is about 2/3rds of desktop. Most of my traffic is mobile. That's kinda just the way it works. People on phones aren't as likely to click on ads (although I think maybe the bigger screens help - love my iPhone 6 Plus)

Only way I have to combat it is try to get more traffic. So far that's worked out okay.

So far in 2015:

Mobile RPM 105.6% of desktop 131.7% CTR of desktop
Tablet RPM 167.0% of desktop 157.7% CTR of desktop

Mobile plus tablet 38.9% of overall earnings 17.1% mobile 21.8% tablets.

All my sites which are html5 responsive have the best RPMs.

My situation is similar to netmeg's. Most of my traffic is mobile but RPM is only 50% of desktop. In the US, it's because mobile CTR is lower. On my German sites, mobile CTR is actually higher but CPC is much lower.

I put a lot of effort into optimizing my mobile sites and I'd love to see higher RPMs. But it seems that I simply have to accept lower mobile RPM.

Mobile CPC prices continue to plunge. My mobile CPC prices are down 35% from the same period last year whereas desktop CPC is up slightly for me and tablet down very slightly. Mobile CPC prices are hurting publishers big and small. Everyone knows it and doesn't know how to fix it. Or is afraid to fix it. It's going to be a LONG time (my prediction) before mobile CPC ever gets to where it needs to be; but won't likely happen until ALL desktops are obsolete. Or until Google removes the option for advertiser to lower their bids on mobile. I still am very surprised Google has not been more aggressive with influencing mobile CPC rates. They (Google) hold all the cards; they're not going to lose big advertise if they start charging more for mobile and still require advertisers "take" mobile impressions/clicks. I feel there is an unknown reason Google isn't pushing more on the mobile advertising front.

Most of my traffic is desktop and tablet, and they have the same RPM. About 10% to 15% of my traffic is mobile. Its RPM is usually lower but some days it nearly rivals the other two.

they're not going to lose big advertise if they start charging more for mobile and still require advertisers "take" mobile impressions/clicks.

They sure are. Every last one of my B2B clients would quit AdWords if Google decided to do that, and I expect they're not alone. There was a pretty big pushback when they made us lump tablets in with desktop bids; it would be even bigger if they tried to do it with smart phones.

People on phones don't usually want to click ads. Forcing them to (or forcing the advertisers to serve ads to them) isn't going to fix that problem.

Everything has a shelf life; no doubt AdSense does too, if they can't figure out how to make mobile work.

Advertisers are not going to quit a program (Adwords) if it is still profitable for them. Business (done right) is black and white - not personal. If Adwords "forces" advertisers to take more higher priced mobile clicks and it say reduces their ROI from say $3 for every dollar spent to $2 for every dollar spent advertiser will absolutely continue to spend as much on Adwords unless they have other sources of leads at the same CPA and value. If an advertisers profitability is already so thin that they can't absorb say 10-20% increase in CPC then time will likely due them in anyway.

When I say big advertisers, I'm talking about $500,000+ a year. They're really the one ones Google cares about. Google won't miss MOST B2B advertisers. There is almost no branding in B2B marketing. B2B advertising is a nightmare compared to B2C. Why do you think Google focuses almost exclusively on B2C?

I'm down to a mobile RPM that's 20% of desktop. I recently switched to ad units (identical sizes of 300X250) which only appear on mobile instead of both mobile and desktop. I think this could be part of the problem although Google separates out platforms regardless.

I'm not going to bother arguing with you, because it will never happen. Advertisers are never going to be forced into paying the same for mobile clicks as they do for desktop, because that would trash the program for both B2C and B2B. The big advertisers are the ones who would scream the most. If you don't choose to believe that, I'm okay with it.

People on phones don't usually want to click ads.

Anyone have a grasp on what percentage of people on phones come back to a site later on a desktop?

FarmBoy

Insofar as I am concerned that's what I do all the time therefore it's 100% for me...however I do know of people who do order all the time on their phones!

I don't have any idea how this could be measured.

For one of my clients I see 3 times better CTR and earnings with mobile especially iOS 7.0 - IOS 7.2 on iPhone and of course on all tablets. It seems desktop users hate clicking the ads.

netmeg, I respect your opinion and understand what your saying, but I'd like to chime in that I disagree that it could never happen. Yahoo has specifically adopted this strategy to push their mobile agenda. They bought Flurry to get the devs, released a dev kit to get the inventory, and then they forced desktop and mobile together with absolutely no ability to adjust bids for either.

I dont think its far off to believe google could do it as well.