Measurement and the Composite Reading

Every arena is measured by between two and twelve indicators. Each indicator yields a reading from 0 to 100: the Hindutva-aligned share of the indicator, computed as

where A is the quantity held by Hindutva-aligned units and O the quantity held by opposed units. Neutral, mixed and unclassified units are excluded from both terms. Where an indicator is not a quantity that can be split (an approval rating, a survey item), its reading is the published share directly.

An arena's reading is the weighted mean of its indicators, using the indicator weights given in each chapter (these sum to 1 within an arena). A domain's reading is the weighted mean of its arenas, using the arena weights. The composite reading is the weighted mean of all 40 arenas:

With domestic weights summing to 88 and external weights to 19.7, the composite is

3.1Classification of arenas

For presentation, arenas are classified as showing an aligned majority (a reading of 60 or more), as contested (45 to below 60) or as showing an opposed majority (below 45). The thresholds are asymmetric around 50 by design: a narrow lead in an arena is treated as contested, not as held.

3.2Office-dependent power

Several indicators, chiefly in the domain of the State and in party finance, depend on which party holds office. The Atlas therefore reports a second composite, computed for a counterfactual in which the BJP holds no office at the Union or in any state, with transactional money reassigned accordingly. The difference between the two composites is the office-dependent share of Hindutva-aligned power. On the baseline, it is 9.0 points (45.7 against 36.7).