<h1>Statutory basis for industrial statistics: survey and administrative data combined, validated and authenticated before finalisation.</h1> Industrial output measurement relies on two mechanisms: the Annual Survey of Industries, conducted on a statutory basis using factory books of account to estimate manufacturing contribution to national income, and the Index of Industrial Production, compiled monthly from administrative data supplied by multiple ministries; both data streams undergo scrutiny, validation and authentication by source agencies and line ministries before finalisation, with quality and methodology reviewed periodically by expert groups and committees.