The work deals with the problem of changes in the relative prices of industrial outputs due to the imposition of a tax. Furthermore, the imposition of a tax induces changes in all of the components of the input-output table. The magnitude of the changes is a function of the degree of forward shifting of the tax under consideration. Although the analysis can be applied to any tax with due consideration to its shifting characteristics, the wellhead tax was selected as an illustrative example for several reasons. The tax has been proposed as an alternative to the existing system of controls and entitlements imposed on the production of crude oil in the United States after the oil embargo of 1974. The wellhead tax is equivalent to the tax on profits when the elasticity of supply of crude oil is zero. The tax on profits in another alternative which has been proposed to replace the system of controls and entitlements. The input-output tables of the U.S. Department of Commerce were analyzed in regard to their sources of data and methods of construction. From this analysis the conclusion was reached that the only possible interpretation of the tables is in "value" terms. That is, dollars for the transactions table and dollars per dollar for the direct requirements table. Three philosophically different methods were developed to analyze the price effects and to recompute the direct requirements table. The three methods yield identical results. The treatment of direct and indirect taxes in the American tables does not agree with accepted concepts of shifting in public finance. Namely, in the tables, indirect taxes are fully shifted forward while direct taxes are not shifted. In this work, simulations were run assuming different percentages of forward shifting for the wellhead tax. Comparison of the results, with analysis by Robert E. Hall, indicates that his study is equivalent to a sixty percent forward shifting of the tax. The analysis of the American input-output tables indicates that studies of tax incidence assuming constant input-output coefficients, such as the study by Henry Aaron, are logically inconsistent for any degree of forward shifting other than zero.