臺灣地下經濟之探討 : MIMIC模型之應用

Abstract

本文首先利用三種傳統的估計方法：通貨對活期存款比率法、交易法與貨幣需求法，來估計台灣地下經濟粗略規模，再進一步利用Joreskog and Goldberger (1975) 所提出的MIMIC (multiple indicators and multiple causes) 模型，將地下經濟視為一個不可觀測之變數 (latent variable or unobservable variable)，同時設定導致地下經濟的原因為成因變數 (causes)，而前三種估計方法所估計出的地下經濟粗略規模作為指標變數 (indicators)。此不可觀測之變數一方面會受成因變數的影響，另一方面也會反應在指標變數上，利用這樣的關係，本文將可以更精確地求出台灣地下經濟的規模。研究結果發現臺灣1962年～2002年地下經濟規模為27％～5.6％，有逐年下降的趨勢。

Several approaches have been used to estimate hidden economy in the literature but they often reach different conclusions. This paper provides an alternative approach to the conventional measurements of hidden economy, in which hidden economy is treated as latent (or unobserved) variable. According the multiple-indicator and multiple-cause model (MIMIC) model, three conventional measurements, the cash deposit ratio, transaction, and currency demand approaches are assigned as indicators for the hidden economy which in turn can be accounted for by a number of factors (causes), such as tax rate and interest rate. Our analysis shows that Taiwan's hidden economy has been shrinking over the past four decades from 27% in 1962 to 5.6% in 2002.