Yksinkertainen on kaunista
(Simple is beautiful)

Pitkän aikavälin kannattavuuden estimointimenetelmien simulointivertailu
(A simulation assessment of four long-term profitability estimation methods)

Timo Salmi and Ilkka Virtanen

English abstract

Four methods for estimating the firm's long-term profitability as the internal rate of return (IRR) of the firm's capital investments are revisited and evaluated using simulated financial statements. The methods of Kay, Ijiri-Salamon, Ruuhela and the averaged accountant's rate of return (average ROI) are analyzed. Our findings indicate that the methods are disrupted by large deviations between the firm's growth and profitability, but in most cases they are insensitive to cyclical fluctuations and to major capital investment shocks. Kay's method fares marginally best in numerical performance, and it is theoretically very well founded. The average ROI method comes a close second. The Ijiri-Salamon method fares reasonably well numerically, but its error is unpredictable. Theoretically, it is the most ad-hoc of the methods. Ruuhela's method has a strong theoretical background, but when its strict assumption of steady state growth is violated, numerically it fares the worst. In the literature's long-standing dispute about the valid ity of the ROI as a proxy for the IRR, our simulation results strongly support the school of thought siding with the validity. Our research conclusion is to recommend applying the average ROI method in the practice of financial analysis. It is in a class of its own as regards pragmatic applicability because ROI is a central accounting concept.