They also created this infographic about the US data.
In the research they undertook here are the factors they found to be of importance:
– The number of backlinks remains of enormous importance – not only the quantity, but also the quality of links differentiates well-ranked pages from those that place more poorly.
– Keyword domains have lost relevance – Keyword domains and the factor “Keyword in the URL” appear to have been devalued by Google
– Quality and diversity count with respect to content – In relation to page content, factors like “length of text” and “number of images” correlate positively with improved rankings -but adding even more text is thus not equivalent to an even better position. This for me is worth investigation in relation to how many words are relevant for a blog article
– On-page technology is one of the basics – A good technological page design is still a basic requirement for rankings in general and the existence of the keywords as well as the existence of H1, H2 and description on-page continues to be important. If you are using WordPress this is easier for you to manage with certain templates, child themes and plugins.
– Social signals correlate very well with better rankings – This does not necessarily mean that social signals are a ranking factor however the URL’s in the top positions show significantly more social signals and their studies in the US and Germany came to the same conclusion.
If you are interested in search engine optimisation for your blog or website you will also find this article of interest about when you should delete old articles or add no follow and no index tags to your content.