Where prediction-market dollars actually sit: each market's 24h volume is partitioned by category, and the published level is the leading category's share. A sociology instrument — it measures what people bet on, not what the prices say.
What feeds the figure at last compute. The weights are the composition — each constituent is a partition of the measure, not a market.
The Mensor reads the market; it does not take positions in it. MATI is a measurement, not a forecast and not a tradable product. Prediction-market prices are risk-neutral and approximate probabilities.