PROBLEMS OF TAX BURDEN 293 interstate comparisons of corporation tax burdens has been developed. The general property tax constitutes the largest part of the combined state and local tax burden on manufac- turing plants, with the probable exception of very profitable corporations in states with fairly high income tax rates. For the purpose of determining the general property tax burden, the only satisfactory approach would seem to be an engineering appraisal of a large number of manufacturing plants in the states which it is desired to compare and a com- parison of the valuations obtained with the assessed valua- tions and tax rates. Investigation of this kind would no doubt show that the variation in assessments for the general property tax in most states would be considerably greater than the variations among state averages. Even though an investigation of this kind should be made, it does not follow that absolute comparisons could be made. In the first place, an appraisal by a competent staff of engineers is sub- ject to some margin of error. Furthermore, the results obtained would be for manufacturing plants in general and not for those engaged in manufacturing a particular kind of product. Before definite conclusions could be reached, the comparisons of the general property tax burden would have to be made on the basis of industries that are in more or less direct competition with each other. For example, a com- parison of the general property tax burden on all corporations in St. Louis might indicate a smaller burden on the average than inacityinan adjoiningstate. Such a conclusion would not be very significant unless it could be shown that manufactur- ing corporations in the other city were engaged in the produc- tion of commodities comparable to those which are produced in St. Louis. On the other hand, if the burden on corpora- tions manufacturing a specific product in St. Louis were found to be larger than on a plant manufacturing the same product in a city in another state. such a conclusion would be of real value. In determining the total tax burden on corporations it would be necessary to include other forms of taxes. These taxes could be easily determined for a corporation with a given capital set-up and a given net income from operations. Usually, however, the general property tax would comprise