Ask a campaign what their vote share was last cycle and you get a single number. Ask them what their margin distribution looked like across booths and you get a blank stare. That gap is where campaigns quietly lose.
Vote share averages hide everything that matters. Two constituencies can have identical 42% shares. One has that 42% spread evenly across 280 booths with narrow leads everywhere. The other has 65% strongholds in 90 booths and complete collapse in 190 booths. The plans those two seats need are opposites.
What a margin heatmap actually shows
A booth margin heatmap plots every polling station on a distribution of winning margins. Booths above a threshold are strongholds. Booths near zero are the swing zone. Booths deep negative are structural losses.
The shape of that distribution tells you three things at once. First, how concentrated your existing base is. Second, how many actually competitive booths exist. Third, how much of your win margin is padding versus real cushion.
Why the average lies
A 4% average lead sounds safe. Break it apart and you might find your lead is coming from ten fortress booths pulling the average up while 40 booths are already losses. Remove the fortress booths from the sample and your average collapses.
That is not a hypothetical. In two of the last three Assembly cycles we studied in Karnataka, the winning campaign was outside the average lead in more than half their own booths.
How to read a heatmap in three minutes
- Count booths above +15%. That is your core base.
- Count booths between -5% and +5%. That is your swing zone.
- Count booths below -15%. That is your structural loss.
- If the swing zone is more than 20% of the booths, this is a winnable seat with the right ground game.
The point is not to memorise the thresholds. The point is that a single averaged number cannot answer any of these questions, and every campaign that plans off a single averaged number is planning off a lie.
