Why your Adsense ads and earnings may fluctuate

One of the many factors that come into play.

[whatcartridge]

There is one possible reason why some people may have higher or lower CTRs and earnings for a day seemingly at random. That's Google testing. One of the Google engineers has said so on the Adsense blog:

"Once we believe a new idea is ready for testing, we have to implement the idea in our ad serving code using the very powerful development tools Google has provided for us. Naturally, all code designed to serve ads to our customers must pass a rigorous review and testing process before release to ensure that we continue to offer uninterrupted service. During the testing process, we typically run an experiment on a small percentage of traffic for anywhere from a few days to a few weeks. We select the experiment traffic randomly so it is as representative as possible of overall traffic; no individual site should ever see more than a small percentage of its traffic involved in an experiment.Because most targeting experiments involve adjustments to the ad-selection algorithms, they are rarely noticed by anyone outside Google. However, we occasionally run experiments that affect the format or display of ads as this is the only way we can verify whether a potential change will provide an overall benefit to publishers, advertisers, and users."

my emphasis added

The question is, how much is a small percentage? Would it be enough to make a difference? I'm sure it would affect lower earning sites more than higher earning sites.

[jomaxx]

Obviously nobody can answer those questions, but anyway what's the alternative? Google never changing anything again? Google introducing algorithm changes without testing them first? Clearly these are not practical options.

[whatcartridge]

Don't get me wrong, I'm not complaining. I realise things will always go up and down, that's just the nature of any business. However, there are a lot of people in this forum looking for reasons why there are ups and downs (even if most of us know that there is no reason - it just happens), so I thought I would give them another.

[incrediBILL]

They should just leave it alone as every time they tinker with format changes my revenues dip and when the formats on my site stopped changing and look like how I originally set them up my revenues went back up.

I'm not sure how a revenue dip benefits me or anyone else, including Google.

Amazing.

[angsuman]

As they say - if it ain't broken then don't fix it

[Nitrous]

>As they say - if it ain't broken then don't fix it

With that attitude we would still be driving model t fords, and displaying banner ads that were not targeted. Test away...

[GoldenHammer]

[.... During the testing process, we typically run an experiment on a small percentage of traffic for anywhere from a few days to a few weeks....]

Now I know why my earnings frequently fluctuate, because my site was always selected to run the experiment..... lol.

[maxgoldie]

The biggest single reason for my earnings fluctuating is that some times for days at a time, I get a spate of poor quality, or just plain misleading ads, the majority of which point to either an MFA or a domain parked site. (earnings go down)

And then, for no apparent reason, things reverse, and I get a spate of tried and true advertisers back on my site (a lot of which are fortune 500s) for a period of time.(earnings go up)

This flux happens even though my traffic levels and new visitor/repeat visitor mix remain fairly stable.

What I wonder is (from under my tinfoil hat) could it be that Google's algo spreads the ads out and around within similar sites, so that all the poor quality ads do not all stick to one site for any length of time?