Everybody talks about the need to provide quality content on your site if you want to rank well in searches. But how do search engines identify quality content?

Successive Google algorithm updates (culminating in the recent Panda 4.1) aim to refine results so that they match the intent of the search query and deliver the most comprehensive, accessible and well-written answer.

Put simply, Google (and other search engines) are always looking for genuine quality content, and are increasingly smart at finding (and dismissing) pages that try to game the system.

For example, Google’s Hummingbird algorithm restructure from last year enables it to better understand the meaning behind search queries as well as the semantics behind content.

So what should you focus on if you want to produce content that search engines will recognise as high quality? Here are five key factors that we have identified:

1. Holistic content

Content should not just be focused on optimising for single keywords – but should cover the topic comprehensively and be based on content clusters, individual subjects or topic areas that are based around keywords and a variety of related terms.

This change is because the Hummingbird algorithm change and the move to semantic search means Google is now much better at recognising the intent of searchers when they enter a search term.

Companies therefore need to include content clusters in order to be more holistic – and, at the same time, make content more relevant for users with different search intentions.

A good way of doing this is to look at content in terms of proof terms and relevant terms, as both have a strong positive correlation with high Google rankings.

For example, for a search term such as “iPhone 6 plus” proof terms such as “Apple” or “mobile” are words that are strongly related to the primary keyword and highly likely to appear at the same time.

Relevant terms such as “bending” or “screen size” are a bit more removed and part of a sub-ordinate topic cluster, but still important.

2. Length of text on the page

Back in 2012 when Searchmetrics analysed the factors that correlate with pages that rank highly in Google, we found a higher number of words on a page had a negative correlation.

That already changed last year, and the trend continues; our Ranking Factors study in 2014 found that the average length of a top ranking result is now around 975 words/8,313 characters.

Obviously this is not just a question of writing more words – search engines are looking for quality content that is relevant and contains content clusters, rather than unconnected, single keywords.

3. Readability of copy on the page

As part of the aim of delivering usable results, Google is also considering the readability of the text – i.e. how easy (or difficult) it is to read particular pages.

We used the Flesch readability scale, which analyses word and sentence length, to assess the legibility of content.

The scale ranges from 0 (difficult) to 100 (easy) and we found that the average Flesch score for high ranking pages is 73/74. For reference, the scale states that content between 60-70 is easily understood by 13-15 year old students.

Generally therefore web content that aims to appeal to a non-specialist audience should be straightforward to read and understand if it is to rank highly.

For more specific search queries covering more academic subjects, results may be slightly different. Consequently, it is important to create content that fits the search intention and the needs of your specific targeted user group.

4. Less advertising on the page

Sites that rank in the top 30 positions generally include less advertising than average according to our analysis. Our findings indicate that Adlinks and Google Adsense integrations both correlate negatively with good rankings.

This continuing change reflects the desire from people to find and read holistic content, rather than be distracted by advertising.

5. The presence of images

While perhaps not worth a thousand words, photos and videos seem to be viewed favourably by Google as well as making a page more attractive to readers.

The top ten ranked sites in Google’s search results tend to have between 6-8 images on a page for example. While it is likely that this will be capped by Google in future, ensuring your content has relevant, high quality images will help when it comes to ranking.

Google is getting better at identifying quality content and its succession of algorithm updates will continue to downgrade the appearance of poor and spammy pages in its results.

If you want to achieve strong, long lasting search visibility then you should make sure that producing a regular stream of high quality content for your target audiences is a key part of your strategy.