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5 November 2020 / Opinion

Share of Search: Everything you need to know and why it matters to your brand

John Jackson / Head of Client Strategy

Share of search (SOS) is probably the most hyped marketing buzzword this year. Marketers from all areas are getting excited about this new metric – with some seeing it as a potential replacement for more costly metrics like share of market (SOM) or even share of voice (SOV). However, those from a digital background are struggling to understand the hype around a metric that has already been in use for years.

What is share of search and what impact will it have on brand and agency-side marketers?

What is share of search?

SOS is the share a brand has of a markets' total brand search volume. This free data can be sourced from Google Trends or Google Keyword Planner.

For example:

Brand A – 1000 monthly brand searches

Brand B – 1500

Brand C – 2000

Brand D – 500

Total market searches = 5000, therefore Brand A’s SOS is 20%



Why is SOS important?

SOS reflects the impact of marketing activity by analysing the interest a brand acquires online through search. 

Whilst the metric has been used for many years within digital marketing, recent research within the broader marketing sphere has highlighted the potential value of the metric in the wider marketing mix.

SOS offers a metric that’s incredibly useful, but crucially, also very easy to obtain. It could potentially be utilised as a proxy for much harder to get metrics like SOV or SOM.



What is share of voice?

SOV = Brand spend / Total market spend x 100

SOV can mean many different things. In this instance, it is used within advertising agencies to help assess media spend. It is a measure of the amount of advertising budget spent by an individual brand.

SOV is also used in performance marketing, both by SEO and PPC practitioners as a measure of how much traffic a brand would get based on visibility and ranking position for a selection of key search terms. For this post, we are going to be talking about the traditional marketing definition.



What is share of market?

SOM = Brand revenue / Serviceable addressable market (SAM) revenue x 100

TAM – Total addressable market – The total market demand for a product or service

SAM – Serviceable addressable market – Potential market demand that your brand could achieve

SOM is a measure that highlights how much of the total market any particular brand has. So, for example, British Gas controls 18.4% of the electricity market compared to OVO that controls 15.8%.



Excess share of voice with SOM

SOV comes into its own when used alongside SOM. When combined, we can work out Excess Share of Voice (ESOV). The below chart highlights how we would do that.

A Brand That Punches


Essentially, brands to the left-hand side of the blue line should expect to grow their market share, brands on the right should expect it to decline.

This acts as a powerful guide when setting media budgets. It helps planners and strategists understand how much needs to be spent to hit certain levels of market share. This helps to demystify the media budget setting process, making it easier to get broader business buy-in. However, there are some key issues with them. Both SOV and SOM can be difficult to get a hold of, and their accuracy is also questionable due to the rise of digital marketing (spends that are not often counted in SOV) and ecommerce.


How can SOS help?

SOS offers an interesting stop-gap solution. By measuring a business’s SOS in comparison to other competitors, we see very strong correlations between that and SOM, meaning that it could be used as a potential replacement.

In fact, more than that, Les Binet highlights that SOS could be a long-term predictor of changes in SOM, with his research showing a strong correlation between the two.



Mark Ritson also believes that SOS could potentially be used as a replacement for SOV. In a piece for Marketing Week, Ritson states:

"Share of voice is a key metric for setting budgets and predicting growth, but digital media make it impossible to calculate accurately. Understanding your share of search queries is a simple and elegant alternative."

However, he is cautious about using it as ESOS, as there hasn’t been a huge amount of research into the area.



What are the drawbacks?

The drawbacks to this are fairly substantial, best summarised by an article by Shann Bigilone

"SOV is a measure of input. A thermostat. But when it comes to your share of search, you’re measuring an outcome. It’s a thermometer, and you can’t really use it to turn up the heat." 

Bigilone highlights that SOS is a measure of outcomes not inputs. In contrast, SOV is judged by advertising spend, not its impact. You are essentially relying on Google’s understanding of the events surrounding the brand you are searching for. This could be an issue as you cannot directly compare what marketing channels are being used and what is being spent. You are therefore having to make assumptions about what is causing the change in SOS. Effectively, you must work out where the heat is coming from.

Another drawback highlighted by Gailynn Nicks is the quality of the data utilised for SOS. She highlights:

"For any brand manager or CMO thinking they can simply take “free stuff” from Google Trends and create a low-cost brand tracker, think about how much work needs to go into setting up a reasonable SoS measure, especially if you want to cover brand/Masterbrand or multiple markets."



Working with the data

Google’s data must be taken with a pinch of salt and drawn on by people who know what they are doing. Whilst the data is there and is free, making it into something useful will take time and expertise. When looking at keywords, the intent has a major impact on what results come back. For example, a search for “united” in Manchester would offer very different results to one in Newcastle.  

SEOers and PPCers spend their time working directly with Google’s data and understand how best to read it. A lot of their time is spent refining and cleaning data, making them a great ally when it comes to analysing SOS data.  

Gailynn Nicks then goes on to highlight another important point,

“What happens when metrics become targets or KPIs?”.

The digital marketing industry has a history of creating KPIs out of metrics (domain authority, bounce rate, time on site to name but a few), and SOS could potentially turn into another one of them. Doing this encourages marketers to focus on the wrong things, diverting attention away from key performance metrics like traffic, revenue and profit. We need to be careful that we do not do the same here.

SOS is reflective of other work we do within marketing, but on its own is essentially meaningless.



Initial conclusions

More work is needed to work out the complete relationships between SOS and marketing performance, but early signs are promising. In fact, it has drawn up a few other areas that SOS could be useful in.



What else can share of search do?

Using SOS as the canary in the mine

As highlighted above, Les Binet showed that SOS can be an excellent predictor of market share. As SOS increases, SOM steadily follows. SOS is also a fast and responsive metric, making it a good way of understanding how well your advertising is performing.

With this in mind, SOS can offer a way of highlighting potential issues before they make a major impact on market share. If tracked closely with marketing activity, it can also help highlight what marketing is working especially well.

These trends will be useful to brands as it will help to identify campaigns that are performing well, whilst also giving a nudge as to when more investment needs to be put into marketing and maintaining SOM.



Using SOS to understand media spend performance

Adele Jolliffe created a summary piece on SOS on the Kantar site. As well as giving an excellent account of the SOS findings so far, she also highlighted an interesting way of using SOS to highlight media spend performance.

“In the example below, it was clear when looking firstly at Share of Voice vs Share of Market that Brand A had a problem: media spend wasn’t translating into SOM as expected."



"Where’s the issue? We might point an accusatory finger at their campaign investments and assume we need to start again.

But, wait! Looking at Share of Voice vs Share of Search we can see that in fact the campaign investments were generating interest in the brand at the expected rate. It’s not the campaign that needs attention: it’s the journey between interest and a sale that’s getting blocked. Point that finger in another direction and get to work!”


Short term and long-term impact on search?

What is also interesting is that marketing appears to have both a short-term and long-term impact on SOS. More interestingly though, is the proportional impact:

“…around 40% of the impact was felt in the short term (the first month) and around 60% of the uplift was delivered over the long term (the following two years).”


Whilst SEO’s have known for several years that ATL advertising has an impact on organic search (volumes and visibility), it is great to see that proven. Moreover, it is interesting to see that Binet and Field’s 60/40 (long term brand/short term activation) even applies within search.




SOS is not a silver bullet, but a useful tool to have in your marketing arsenal. It can act as a proxy for some of the more expensive and difficult to obtain measures, making planning budgets far easier. It can also be a reasonable predictor of overall performance, making it a very interesting metric for marketers to track.


5 takeaways for marketers

  1. Get tracking – Talk to your SEOs and get them to set up some SOS tracking campaigns against your competitors. Use this as a “canary” to better understand the impact of your campaigns and the potential trajectory of your brand.
  2. Test Test Test – This is still a brand-new metric and as such, we cannot be 100% sure of its impact. It’s important to test how it compares to your other metrics. Look for correlations to understand what SOS can tell you.
  3. Don’t forget the basics – If you can get access to SOV or SOM data, then keep doing so. Use SOS as an additional component.
  4. Consider the impact of SOS on SEO – It’s been speculated for a while that there is a direct correlation between brand and ranking position. The higher your brand search volumes, generally, the better you rank. This makes SOS a potential predictive measure for organic search performance, as well as market share. Tying together your organic search and broader marketing campaigns could be a great way of making the most of this.
  5. Google is not infallible – Remember, this data is not perfect, so do not treat it as such. Treat this as a useful metric, but not a performance metric.