Share of Voice is the percentage of the first ranking position traffic you should be receiving based on your keyword set being viewed specific to those in Research Grid or managed keywords in Rank Intelligence, compared to your competitors. It can be viewed in the platform for all keywords or for a specific keyword tag. This metric is calculated by looking at each keyword's estimated CTR, which is determined by rank position (1 - 10), and multiplying it by the keyword's search volume. This number is then summed and divided by the total search volume multiplied by the CTR of the first ranking position. This would be the same as dividing Estimated Traffic by Traffic Potential. This is similar to Share of Market, where the search volume denominator is the key differentiator between Share of Market and Share of Voice.
In scenarios where a single domain has multiple listings ranking for the same keyword in the top 10 positions, the Estimated Traffic can be greater than the Estimated Traffic for position 1. For example, if a domain ranks in position 1 for every keyword in a set, then their share is 100%; if a domain ranks in position 1 and 2 for a keyword in the same tag group, their Share of Voice will be greater than 100%.