Central Perk: SEOmoz Daily SEO Blog

luni, 22 august 2011

SEOmoz Daily SEO Blog

Panda 2.4 and Analytics Session Update Rolled Out Simultaneously

Posted: 21 Aug 2011 02:15 PM PDT

Posted by MikeCP

On August 12, Google announced that their high-quality sites algorithm, otherwise known as "Panda", had been rolled out for all languages save for Korean, Chinese, and Japanese. The change is said to impact 6-9% of users' queries, down from the 12% seen in the initial Panda update back in February. Though the official announcement post doesn't make mention of this update's effect on English queries, Vanessa Fox at Search Engine Land reported that a few minor changes were made, but there shouldn't be a substantial impact.

Only 9 hours earlier, the Google Analytics blog announced a change to the way visits are to be calculated, effective immediately. We'll get into just how this changed in a bit, but according to the announcement post, "most users will see less than a 1% change".

So, with all of of my clients being US based, I wasn't expecting to see much of a change from Panda, and I can deal with a 1% change in Google Analytics. However, apparantly two insubstantial impacts make a big one, because upon checking Analytics on Monday night, I was surprised to see this:

Organic traffic is up 30% week over week

This particular client saw a 20% drop from the initial Panda update back in February, and we've been working to get back to previous levels ever since. Was this the recovery we'd been hoping for?! After all, the site in question hardly fit the mold of the typical 'Panda-lized' site. Though we were told not to expect much change to English SERPs, I was hopeful.

Google's decision to push Panda 2.4 and the Google Analytics update on the same day wreaked havoc on my ability to see what was really going on. I can only imagine that some of the first-time Panda sites using Google Analytics are reeling right now.

Google pretty frequently points out that many of their teams do not share information intentionally. As an example, the search team has stated time and again that sites that run AdSense advertisements do not receive preferential treatment in the SERPs, despite the fact that this would positively affect Google's bottom line. Similarly, Google's other web properties like Maps, Places and Knol (purportedly) aren't given any special treament, either. Perhaps this is a similar case, but it's borderline irresponsible for Google to have pushed these two updates simultaneously. I believe the onus falls more on the Analytics team, but it's hard to know really.

Seeing Through Pandalytics 1.0

In trying to get to the bottom of this issue, it's important to understand how visit calculation in Google Analytics had changed. Straight from the announcement blog post:

What’s changing?

Currently, Google Analytics ends a session when:

More than 30 minutes have elapsed between pageviews for a single visitor.

At the end of a day.

When a visitor closes their browser.

If any of these events occur, then the next pageview from the visitor will start a new session.

In the new model, Google Analytics will end a session when:

More than 30 minutes have elapsed between pageviews for a single visitor.

At the end of a day.

When any traffic source value for the user changes. Traffic source information includes: utm_source, utm_medium, utm_term, utm_content, utm_id, utm_campaign, and gelid.

Ultimately, this change is about assigning proper attribution for conversions and engagement. As Michael Whitaker points out in his blog post, previous to August 11, it was possible to find plenty of keywords with pageviews and unique visitor counts but 0 visits. Grab the custom report from his post to see for yourself, or take a look here (with filter applied so that visits = 0):

Visits set to 0 before the change

Now, each new keyword is going to count as a visit, which is really the right move. See this same report set to a date after the change:

Now more empty visits

Some Examples

So what is actually going on here? Well, here are a few real-world scenarios where the way that visits is calculated is changing.

Scenario 1:

User searches Google for "Product Name" and clicks on your AdWords advertisement.
User leaves site and searches a few more times, click on competition and comparing prices and features.
User ultimately decides to with your product, Googles "Your Brand + Product Name", clicks your organic listing, and buys the product. This whole process takes less than 30 minutes.

Previously, the second visit to your site would still count towards the original query, "Product Name". The conversion is attributed to the most recent non-direct source, so "Your Brand + Product Name" gets the credit, but would not appear in your organic keyword report (or would with 0 visits attached). Now, this counts as 2 separate sessions, and "Your Brand + Product Name" will appear in your organic keyword report with 1 visit.

Scenario 2:

User searches "Product Name" and lands on your site.
User exits and visits a few other sites.
User searches "Slightly Refined Product Name", lands on your site, and buys.

Again, now this counts as two visits, where it used to be one. In fact, for this particular client, I believe this scenario was pretty common, as average query length increased significantly, suggesting users were refining their queries.

So Is My Traffic Up Or What!?

Still, in my example above organic visits were up over 30%. This is quite a bit more than the expected 1% change from Google Analytics, and the "insubstantial impact" from Panda 2.4. How can I know if there is any Panda recovery at play? If I want to compare apples to apples, the answer is going to have to come from my visit-agnostic numbers: Pageviews and Unique Visitors.

visit count
Visits up 30%
unique visitor count
Unique Visitors only slightly up
pageview count
Pageviews also only slightly up

So it is pretty obvious from the images above that while traffic is on the rise, it's not quite up 30%. It does remain pretty difficult to tell if there was any sort of Panda impact at all, or just a natural growth from some recent link building successes.

Google Pushes an Update to Analytics

Another factor at play in some of this data is that Google acknowledged a bug in the original rollout of this change, and updated their announcement blog post on the following tuesday:

We identified an issue responsible for unexpected traffic changes following our recent update to how sessions are defined in Google Analytics. A fix was released at 2pm PST Tuesday August 16th. The issue affected some sites using the following configurations:

If a user comes to a customer’s site with a space in some part of their traffic source data, then revisit the same landing page during that session by refreshing the page or later pressing the back button, a new session will be created for every hit to that page. (Clicking a link elsewhere on the site that leads back to the page should not matter.)

Google Analytics implementations using multiple trackers (an unsupported configuration) are also affected when a space is included in the traffic source data. These sites will see fewer visits from new visitors, and more visits from returning visitors (with some variation due to different implementations).

Taking a look again at the visits report above, this bug obviously affected the site in question, as visits after Tuesday dropped considerably. Still, the overall effect here is a change significantly higher than a 1% increase.

Again, non-English sites using Google Analytics that are seeing Panda for the first time may be in for a bit of a headache. I'm hoping I was able to shed some light on this problem.

Do you like this post? Yes No