Share of Voice (SOV)

What it is:

A brand's advertising weight as a percent of the total advertising weight of the entire product category.

In addition to a brand, it can be calculated for a company (Progresso), product line (canned soup), or a particular market (New England). It is your percentage of advertising relative to that of the entire competitive set.

It reflects the extent to which your customers are being influenced by your ads versus those of rivals who also try to get their attention with similar messages. Long-term analysis shows that brands that increase their share of voice with powerful advertising stand a better chance of increasing their market share.
                    

                             SOV =           brand’s expenditure      
                                             total category expenditure

Example: