If you are curious why your website's page ranking has tumbled down, first check your Webmaster Tools for a penalty notification or crawl errors. In the recent Webmaster Help video, Google's head of Search Spam, Matt Cutts elucidates how you can determine whether your site ranking is a result of an algorithm penalty or poor content.
Check out the video where Matt explains how webmasters can detect whether their site has been affected by a particular algorithm change of Google.
The question tossed was:
“How can you tell if your site is suffering from an algorithmic penalty, or you are simply being outgunned by better content?”
To this Cutts replied that first and foremost you should check the Manual Actions section in Webmasters Tool. It is likely that you have launched and then forgot to remove the noindex. Matt also mentions to check the Webmaster Tools Crawl Section for crawl errors which are making it difficult to reach the site.
Matt said that Google considers algorithm changes as a part of the holistic rankings and not as penalties. In 2012 Google rolled out 665 different changes to how Google ranks search results. Since Google is continuously unveiling changes to its rankings, algorithm changes which make less impact, like Panda, are less likely to be announced. Whereas changes like the Penguin update, which targets webspam, are announced along with a date so that webmasters can trace out the changes and rectify the errors.
According to Cutts it is hard to determine whether the drop in the ranking is a result of a penalty or poor content. However, the good news, said Cutts, is that webmasters can always work upon things and recover their site's rankings. Since rankings are algorithmic, Matt suggests that webmasters should keep a track of and weigh up what other higher ranking sites are doing, that their site isn’t, for Google to revise and restore their website ranking.