SEO Ranking – A Correlation Study

The Data Collection Background

I have decided to publish some data based on an in-depth study of SEO ranking factors in the UK menswear category. The study uses recent data from a variety of sources. These include and SEMRush.  Rather than simply using pure ranking data I have used actual estimates of organic search volumes. This volume is taken directly from SEMRush, which estimates volumes by each keyword based on Google’s search volume and estimates a click through rate based on ranking. The correlation study looks at the performance of 10 selected menswear websites and compares them across 11 ranking factors.

The Selected Correlation Factors

Compared to many other studies on ranking factors I have attempted to use less esoteric sources of data. Most of these can be found without a subscription and should accessible to people without a high level of SEO knowledge. The eleven correlation factors and their sources are as follows:

  1. The number of pages indexed by Google
  2. The number of high ranking keywords – SEMRush
  3. Moz Page authority
  4. Moz Domain authority
  5. Total Root links – Moz
  6. Total links – Moz
  7. Facebook Likes – Moz
  8. Facebook Shares – Moz
  9. Tweets – Moz
  10. Google+ clicks – Moz
  11. Google Adwords PPC spend

Correlation Values

Correlation values have been calculated using the “Correl” function in Excel. For the uninitiated correlation values range from +1 to -1. +1 indicates a perfect positive correlation and -1 indicates a perfect negative, or inverse, correlation. A value of 0 (Zero) indicates no correlation. Scores above 0.75, either negative or positive could be considered as strong correlations. Likewise, scores below 0.5 could be considered as weak.

A caveat in all correlation studies is that not all correlations are the result of causation. Just because it rains on Tuesdays and Thursday doesn’t mean by naming a day with a T causes it to rain.

The Correlation Results

Each of the correlation factors was tested across the 10 websites in relation to the volumes they achieved. In any event, the range of correlation scores ranged from a negative 0.13 to a positive 0.98. The scores were then plotted and ranked. The chart of these results is shown below:

SEO Correlation Factors Mens Clothing

SEO Correlation Factors Men’s Clothing

If you click on the correlation factor chart you will be able to see the full sized version.
The surprising result is how at 0.98 PPC expenditure correlates so strongly with search volume. According to this study much stronger than the number of root links (0.75), Domain Authority (0.7) or Page Authority (0.66) as measured by

Against this, towards the other end of the scale, total links and most social media measures, even Google+, are seen to be weakly correlated.

The Line of Best Fit

In order to demonstrate how the data for PPC spend and organic search volume correlates, I also provide a graph. This uses a line of best fit.

SEO Correlation Factors PPC Spend

SEO Correlation Factors PPC Spend

Data Limitation

The first thing to establish is the nature of data accuracy. All the measures used are effectively estimates and are therefore inherently flawed to some degree. This is because each measure used is largely an estimate based on a sample. There is, therefore, firstly a risk of sampling error. Secondly the actual numbers used are from a collection of samples that themselves are algorithmic. Most importantly, the product that all the correlation factors is measured against is an estimate of organic search volume as provided by SEMRush. As I know from studies of websites where I have access to the real figures, the SEMRush data can be wildly wrong. However, the SEMRush data is based on accurate rankings taken from the database and all the websites are given equal treatment in relation to rankings and projected volumes. Secondly alternative  sources of data, say using Majestic rather than Moz as a source of link data or website authority, may provide alternative values and, therefore, correlations. That all being said, again all sites in the study are treated equally. If there is a systematic error in any one measure, then that error is applied equally across all sites.

Market Power and Brand Strength

The last error is perhaps the most obvious. Are we comparing a comparable set of websites? When you study the “Line of best fit” chart you will notice that the PPC expenditure behaviour of the ten sites can be clustered into four distinct groups. One site’s spend is recorded as zero. Four websites spend up to £20k per month. Two sites between £30 and £40k. And two large sites spend between £95 and £120k. In my opinion, the spread of PPC expenditures is effectively a surrogate for business scale and market power.

Based on a wider analyses of all of these factors, perhaps market power, or brand strength is the real determinate of rankings and, therefore, volumes. In the case of the UK menswear market, a bricks and mortar retail network, a presence in above the line marketing channels, digital PR, CRM and email marketing activities are what is effectively being measured. If you were a challenger brand up against an online retailer such as Tesco or Marks and Spencer would you expect to outspend and outrank them with your limited budgets and resources. Having a large PPC budget may be a reflection of how well your perform commercially. Logically, if you perform well in organic search you could create the financial resources to invest in PPC activity. So PPC becomes the product of the correlation analysis, rather than the other way around.

At the moment, all of the market power factors identified in the above paragraph are outside of the scope of this present study. However, I plan to return to them in a future study.


Search Marketing and Customer Engagement

The aim of search marketing is to engage customers. To attract them to your website and develop their interest. Once the web visitor is engaged you have the opportunity to persuade them to undertake an action such as complete a purchase or make an enquiry.

The easiest and most profitable way to attract a website visitor is to own a strong and relevant brand that delivers brand based searches. Whether the method is paid or organic search, brand based searches have the highest propensity to convert.

Widening the Zone of Customer Engagement

Widening the Zone of Customer Engagement

Depending on your business’ scale and standing your brand may not generate large volumes of online searches. And secondly, brand searches are not the only way to attract profitable customers. Specific searches closely related to your products and areas of expertise will also yield profitable interactions. And it is in this area of search marketing activity where effective SEO and PPC Management will yield the best results.

The Customer Engagement Matching Process

  1. Match brand relevancy and saliency to customer product and service needs.
  2. Match your communication and persuasion efforts to the information needs of customers.
  3. Ensure that your website, and other marketing collateral, is consistent with and renders well on the devices and media used by your target customers.
  4. Ensure you understand how your customers utilise search.
    When, where and how? How search interacts with other elements of the communication mix.

By matching your search and digital marketing activities to those of your chosen customers, you widen the zone of customer engagement. At Simply Clicks our aim is to assist you in making this process as straightforward and effective as possible.

If you would like a discussion about Simply Clicks’ services please fill in this enquiry form.
Alternatively, during UK business hours, please call us on 01233 670006 or 07984 300050.


Google Removes Adwords Keyword Search String Data

The paid search industry has been buzzing with rumours and actual facts about Google’s latest move to remove the search string from Google Adwords searches.

The search term data is still available in Google Adwords search query reports and still available within matched search query reports in Google Analytics. However, third party systems that parse the search string will no longer be able to do so. See this example from a Statcounter report that I have just run.

Analytics Data Searches 11-4-14

Analytics data searches minus the keyword

As this image taken from a Statcounter report shows 4 of the 6 paid searches are now showing “Keywords Unavailable” and look remarkably similar to the organic searches next to them.

Apparently the data is still available via a Google API and many of the third party vendors of Google Adwords software have mounted major PR offences to push this information out into the search marketing community.

Meanwhile, a Google Analytics matched search query report covering the same period shows all the keyword detail.

The most comprehensive assessment I have seen so far is by Larry Kim on Search Engine Land.