esov explorer
Excess share of voice: how much more you spend than your market share suggests, and what that does to share over a year.
What is market share?
Your share of the category's sales (or volume). If your brand sells 20 of every 100 units bought in the category, your market share is 20%. This is the "SOM" on the slider.
What is share of voice?
Your share of the category's media spend. If the category spends 100 on advertising and your brand spends 25 of it, your SOV is 25%. This is spend, not reach or impressions, and it is measured against the category, not the whole market.
Both sliders are percentages. The gap between them is your ESOV, in percentage points (pp).
In plain English
Learn how it works
Percentage points vs percentages
When you subtract one percentage from another, the result is in percentage points (pp), not percent. If your share of voice goes from 25% to 30%, it has risen by 5pp, but the rise is 20% relative to where it started.
ESOV is a difference, so it is always in pp. Your ESOV of +5pp means your SOV is five points higher than your market share.
The rule, in words
The idea is simple. A brand that spends more than its share of the category's media tends to gain share, and a brand that spends less tends to lose it.
The 0.05 comes from the finding that 10pp of ESOV drives about 0.5pp of share growth per year. Divide 0.5 by 10 and you get 0.05, which is the slope of the line on the chart.
The line goes through the origin, so an ESOV of zero predicts no change. Every extra point of ESOV adds 0.05pp of growth per year.
How to read the chart
The horizontal axis is your ESOV. The vertical axis is the share change the rule predicts for that ESOV. Your brand is the dot, and it sits on the line.
The background colors mark three zones. Maintain is the grey band within ±2pp of zero, where share should stay roughly flat. Grow is to the right, where share should rise. Shrink is to the left, where it should fall.
The ±2pp band is a choice made for this tool. The rule itself doesn't draw a line between maintain and grow.
The math, with your current numbers
Glossary
- SOM (share of market)
- Your share of category sales or volume.
- SOV (share of voice)
- Your share of category media spend.
- ESOV (excess share of voice)
- SOV minus SOM, in percentage points. Positive means you spend more than your share.
- pp (percentage points)
- The unit for a difference between two percentages. 30% − 25% = 5pp.
- Predicted share change
- The rule's estimate of how much your share moves in a year, ESOV × 0.05.
- Regression line through the origin
- The straight line of predicted change. It passes through (0, 0), so no excess spend means no predicted change.
- Maintain band
- The ±2pp zone around zero, used here to decide when share should hold steady.
Read this before you use the number
The 0.5pp figure is an average across categories. It comes from cross-category analysis. Any single category, and any single brand, can sit well above or below it.
Smaller brands and new launches typically need higher ESOV. A brand with a small share has to outspend its share just to get noticed, so the slope in this tool understates what a small brand needs to grow.
SOV here means share of category media spend. It is your share of the spend in the category, not impressions, reach, or the share of voice in any one channel.
The maintain band is an assumption. This tool treats ESOV within ±2pp as "maintain." That threshold is a choice for display, not a finding.