HM Treasury seeks to answer all parliamentary questions that do not incur disproportionate cost. Disproportionate cost is determined via a disproportionate cost threshold (DCT). The current DCT is £800, announced in Parliament by ministerial statement on the 20 January 2010.
The calculation of DCT is based on eight times the average marginal cost of answering written PQs. Marginal cost excludes the fixed costs of parliamentary branches and departmental overheads.