On Friday, Google launched “How Search Works” in an effort to inform the public exactly what Google does. The centerpiece of it all was a large infographic filled with broad information about how the search engine crawls and indexes the web, how their algorithms work, and how Google fights spam. With the infographic, Google also released tons of resources that SEOs will find of interest.

One of those resources was the official release of Google’s Search Quality Rating Guidelines for the first time ever. Many have already seen a version of this document, as an older, edited version was leaked and circulated quietly already. What is interesting is how different the new version is from the one passed around in the past. The non-public version of the document clocked in at 161 pages, which makes the new 43 page version feel slim.

It is possible Google chopped down the version they actually use for public release in order to maintain a small amount of secrecy as to how Google’s human search quality raters grade results, but it is also possible the company has been steadily revising and streamlining their guidelines over time.

To understand which document you should put more weight in, you need to compare what has been changed, and what has been left in. For example, the third and fourth parts of the document have been completely cut, removing detailed guidelines on how to rate pages, how to gauge the reputation of a website, and even specific examples of public webpages with example ratings. Matt McGee took the time to document every change to the guidelines before their public release. It is up to you to decide which version you should favor.