Logfile Analysis Vs. Client-Side Visitor Tracking
by matt @ 5:28 pm. Blogged under Web Hosting, Banner Advertising, Rich Media
2007 seems to have been the year of web stats comparison questions for me. I don’t remember a previous year where so many people asked me which of their web statistics data tools was telling the truth. The main issue is that whether you’re looking at a logfile analysis report from WebTrends, or a client-side tracker like Google Analytics, both are correct in their own way – you just have to understand their methodologies. The main difference is that logfiles track all server activity – from browser based surfing to Googlebot visits and non HTML file downloads (PDFs), client-side scripts only run for browsers used by real people viewing HTML pages.
Generally, most people want to know which is the best tool to quote for online advertising purposes or for analysis of real visitor browsing behaviour. To do that correctly you really have to turn to a client-side tracking application like Google Analytics, this ensures that the spiders and robots are discounted, cutting page view data reported by log files by around 30% (in my experience) and affecting ‘session time’ (although I’ve not figured out whether it inflates or deflates it yet as who knows how long a crawler stays on a site each day – possibly just seconds, or once a month for 20 minutes).
Digital ad servers like Doubleclick, which themselves use client-side code to serve adverts, will produce ad impression data which excludes automated crawlers – which is why Google Analytics data will usually be quite accurate. There’s not really much point in giving the outside world a false view of how busy a website is from log files if their expectations on ad delivery will be dashed. With that in mind it is sensible to take around 30% off of log-file sourced page impression and visitor data. 30% is my average, I’ve seen some sites with a 15% discrepancy and some with 45%, hence I play it safe at around half way. Almost a year since my last article I still hear people quoting ‘hits’… which isn’t a realistic measure of anything.
Technorati Tags: web stats, web statistics, web traffic, user analyise, logfiles, webtrends, webaliser, google analytics, banner impressions, online advertising
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August 11th, 2007 at 12:16 pm
You might want to check out GoStats, it’s worthy stats tracking alternative.
August 11th, 2007 at 1:28 pm
Well I tried - Internal Server Error…
August 11th, 2007 at 1:46 pm
That was a temporary problem with the web server. (All counters were functioning ok through the problme and no stats were lost. the only outage was to viewing the stats - a brief moment of a few minutes)
-Maybe you’re bad luck?
August 11th, 2007 at 1:53 pm
So Yes, the counter service is reliable!
August 11th, 2007 at 11:52 pm
No risk at all. Google and GoStats both have reporting delays. (where no hits are lost). GoStats just doesn’t have nice error page like Google does.
-By the way, if you’re keeping track, Google had 3 reporting delays last month. GoStats had one this month, one last month.
-You don’t have to ditch Google analytics, you can use both GoStats and Google at the same time. There is a real risk that you will like GoStats better however.
August 12th, 2007 at 9:47 am
I have been using GoStats.com for a couple of years now.
I have tried many other tools too.
The have been great, I am not sure about those delays you guys are discussing, but GoStats are a real value add for facilitating our decision proces.
August 12th, 2007 at 4:41 pm
When GoStats designs a nice error page and becomes a name you can trust, I welcome you to give the service a test drive. Attention to detail is important to GoStats too.
-Did you go through the same such strict criteria for that map stats widget in your sidebar?
August 12th, 2007 at 5:01 pm
Richard, I think you’ll find you’re debating with somebody anonymous called ‘LOL’ and not the owner of this particular website.
August 12th, 2007 at 5:32 pm
Hmmm. I had suspected that given the different name title - but I wasn’t sure so I didn’t press that issue. The staunch opposition to my suggestions and quick cold nature responses did also give off an odd hint that something wasn’t right. It would be interesting to find out where on earth that anonymous caller is from. Usually real site owners will sign with thier own legitimate site name/url.