Effective CPM fluctuation

[hanuman]

is 200% fluctuation in Effective CPM overnight is normal? what can be the reasons?

[hunderdown]

My daily effective CPM varies (from one extreme to the other) by as much as a factor of five. So your 200% variation doesn't surprise me.

SOME possible reasons:
--differences in weekday/weekend traffic
--small number of clicks (if that's the case for your site)-->one visitor clicking on high-value ads can skew a days' results.
--new AdWords campaigns or end of old ones.
--Smart Pricing.

I'm sure others can come up with other possible reasons.

[uncle_bob]

For most sites a 200% fluctuation is pretty normal. Even weekly figures can fluctuate by that amount. Overnight you can never trust the adsense figures, wait until the next day before counting your chickens (or whatever currency google pays in)

[europeforvisitors]

I've never seen such extreme fluctuations, but my site covers a lot of different subtopics, so CPM tends to stay within 20 to 25 percent of the mean in any given month.

A good rule of thumb is:

more pages + greater variety = less day-to-day variation.