مدل سازي اقتصاد زيرزميني با روش منطق فازي

Modeling The Unederground Economy Using Fuzzy Logic Metod (F.L.M.)

The availability of date for the size of the underground economy is important for macroeconomic policy. We use fuzzy set theory and fuzzy logic !o construe! an annual time-series for the (unobservable) Iran underground economy over the priori 1343 to 1378. Two input variables are used - the effective tax rate and an index of the degree of regulation. The resulting underground economy time-series is compared with one previously constructed by the second author using a structural Multiple Indicators, Multiple Causes (MIMIC) model. The tow approaches each yield seusiblt, but somewhat different, pictures of the Iran underground economy over his period. The fuzzy logic approach to this measurement prohlem involves several subjective judgement, hut our results are quite robust to these choices.