7. Conclusions 
The main purpose of this paper was to disprove the assertion of Jerzy Osiatynski that it cannot be theoretically proven that the twolevel system of prices used in East European countries, creates a systematic price bias in the macroeconomic indicators. Osiatynski correctly pointed out that the problem is much more complicated than it is usually believed. The main complication results from the fact that the imposition of turnover tax influences not only the level of prices, but also relative prices. Nevertheless, he was wrong in claiming that the change in relative prices is absolutely unpredictable and that there is an equal chance for each indicator to be biased upward or downward  except in the case of “laborvalue prices”. 
This paper has shown that: (i) the price bias can be easily detected and measured not only at “laborvalue prices”, but also at "material value prices” and at “capitalvalue prices”; 
(ii) the likelihood of the price bias can also be established for “production prices” and for “cost prices”, if measured on specially standardized output vectors; 
(iii) the extent and direction of price bias can be empirically measured by decomposing the bias into two parts: the part which is due to the changes in relative prices, and the part which is due to the differences in the levels of retail and wholesale prices. 
In section (4) of this paper, it was also shown that certain macroeconomic indicators can be made internationally comparable without recalculating statistics of the involved countries into the same price system. It is sufficient to measure the indicators at their own artificially computed price vectors or on the specially standardized output vectors. It was also suggested that the dominant characteristic roots of certain matrices may serve as the best unbiased measures of basic macroeconomic indicators. 



