asked the Minister for Finance further to his Financial Statement of 7 February 1979 that the revenue estimate of £2,092 million "is based on a 6½ per cent growth rate for the economy" and "assumes a continuation of the buoyant conditions of 1978" and further to the statements in his written reply of 15 February 1979 concerning income tax receipts for 1979 that this estimate "was based on macroeconomic estimates and forecasts of relevant economic variables" if he will now specify the "variables" and "data" used and specify the "adjustments" made and "in the light of special factors affecting the income tax receipts" if he will specify the alleged "special factors" referred to in the reply.
Written Answers. - Revenue Estimate.
137.
The Deputy will appreciate that a wide range of economic variables have to be taken into account in estimating income tax receipts, such as the level of employment, output, imports and exports, incomes, and so on. In applying econometric techniques to these variables, adjustments have to be made for any significant variations in past trends as well as individual items affecting the income tax receipts in 1979 and other years. It is not the practice to publish the detailed calculations underlying the tax revenue forecasts.