Discrepancy between Adsense pageviews and server logs

Recent discrepencies seem rather large

[seoArt]

It seems the past few weeks that my page impressions reported by Adsense are only half of what is reported by my server logs. (And every page on my site has Adsense)

Does anyone know what the cause of this can be? Are my ads not showing up on some computers or certain browsers? Or is it just a discrepancy in reporting (what Google considers a page impression is not what my server considers a page impression)?

My concern is that I could be missing out on potential adsense traffic.

There have been times in the past, when these stats matched up very closely. Also of note is that as my site's traffic has increased significantly, the discrepancy has become bigger.

[Powdork]

Are you sure your not looking at page impressions versus ad unit impressions? They changed that recently on the reports page.

[Sunflux]

There are a number of things that can prevent ads from showing... disabling JavaScript, running ad blockers, caching pages, not waiting for ads to load, and so forth, so I'd expect maybe 15-30% difference, but 50% does seem a bit high.

[seoArt]

Powdork, my adwords interface says "page impressions."

Upon visiting my site, everything seems normal. And still yesterday, again, Google is reporting about 50% of the page impressions that my server logs report.

I hope the clickthrough data is correct! Who knows?!?!

[Powdork]

Powdork, my adwords interface says "page impressions."

That's the point. Up until very recently they only gave you 'ad unit impressions'. Then they switched to offering a choice between 'ad unit impressions' and 'page impressions' with page being on by default. So if you have multiple ad units on some pages it would look as though your impressions had fallen.

[seoArt]

That could have happened then.

It still concerns me that Google thinks I get half of the Adwords page impressions that my server reports.

Any other ideas why this could be? Has this happened to anyone else?

[Powdork]

times like that it's good to head into the raw logs, check things out and see if there any major violators you need to block. It's hard to say because all stat programs differ in what they count as visitors and what not. For instance, your stat program may be counting all kinds of bots (Googlebot, Slurp, MediaPartners Bot MSNBot, etc as visitors. Since they don't call the js it is never counted as an impression by Adsense.

[edd1]

I don't think the page impressions thing is working yet. We have two adblocks on each page and the page and ad views give virtually the same results. I'm sure it will come good soon. I hope it does as it would make life a lot easier!

[seoArt]

edd1, are your page impressions in adsense close to your server logs?

[edd1]

I believe they are twice as much but won't be able to check until the end of the day. Will let you know but pretty certain.

[geldmacher]

Some general reasons why the PIs reported in the Adsense stats are lower than in your server logs are mostly bots, people with ad-blockers, download tools, etc.

But what I'm experiencing is that my Adsense reported PIs are much higher than my server log PIs. In fact they're about 99% of Adsense ad block impressions (which seem to be right). I have one normal ad unit on my page and an Adlinks box.

There's definitely a bug in the Adsense PI reporting. At least for me.

[seoArt]

Well, I'm also realizing now that my clickthrough rate has gone up about 5-8% since this discrepancy started (when traffic went up at the same time). So maybe Adsense just isn't reporting PI's correctly (It could be buggy like the last post said).

If Adsense PI's had increased with my traffic increase (as my server logs report), then my clicthrough would have stayed about the same.

[seoArt]

Ok, this is getting ridiculous now. Yesterday my server is reporting 5,011 page views, and Adsense only reprts 1905 PI's.

That's 38% of what my server is reporting!

I recently started showing up #1 on Yahoo for a one-keyword search, "counseling". Could that be the reason behind this? Is my site getting hit by a bunch of scraper site programs?

[Powdork]

You have two ad blocks on each page which means 1905X2=3810. 3810/5011=76%. That means 24% of your users are either not calling the javascript or are visiting your pages without adsense.

[jomaxx]

If you really have some pressing need to match up your server logs and AdSense's stats, put in a tracking image that is delivered via Javascript, adjacent to your AdSense code. THAT should deliver an accurate count of AdSense page views.

Server stats that can't distinguish between a human and a robot will not ever match AdSense's reported numbers and there's no point comparing them.

[seoArt]

Powdork thanks. I'm not sure if the math is right though. The PI number should be the same regardless of how many ads are on the page. The server's number should be the same type of measurement (minus the "ghost" visitors I'm getting that don't see adsense). Your comparing Ad impressions to PI's. And I only have two ads on a few pages. The banners are fastclick.

Jomaxx thanks, I think I'll try that. And the reason I am concerned about the difference is because there may be a reason I have some control over that Google is missing some of my ad impressions. I could be missing out on money. My site's traffic has gone up a lot, while my earnings have not.

[Powdork]

Your comparing Ad impressions to PI's. And I only have two ads on a few pages.

Yep, my bad.
Here are some things to think about.
1. Subtract the views from pages that don't have adsense.
2. Is your stat program counting root.js or swap.js as a view?
3. When someone goes from state.htm to state.htm#city is your stat program counting that as an extra view? The Adsense code doesn't get called again.
4. Set up channels so you can find out where the discrepancies are. It's a good idea anyway.

The answer lies in your logs.