由於利率平價以及購買力平價理論對於匯率升貶的解釋力日漸薄弱，因此本文利用投資者風險趨避程度同時對於國際資本流動(capital flow)與匯率皆具有影響力的特性，提供匯率浮動的依據，換言之，本文將著墨於以中所得國家的資本流動作為解釋變數，對該國貨幣與美元間的雙向匯率(bilateral exchange rate)進行縱橫資料迴歸(panel data regression)。
在實證結果中發現，中低所得國家(lower-middle income countries)資本流動對於其貨幣兑一美元的雙向匯率不論在解釋力或顯著性的表現上整體而言皆優於中高所得國家(upper-middle income countries)，並且於文末有風險代理變數(risk proxies)對中低所得國家貨幣匯率的影響力亦勝過中高所得國家作為佐證，符合文章開頭「中低所得國家與美元間的雙向匯率隱含較高相對風險」的假設，說明一國匯率的組成不僅包含利率或/與購買力的因素，也同時反映該國投資環境在國際資本市場中的風險高低。

Since the explanatory power of interest rate parity and purchasing power parity toward exchange rates have become weaker nowadays, this article would like to make use of the property that the risk appetite of investors could probably have effects on capital flows as well as exchange rates simultaneously, in other words, we are going to put emphasis on penal data regression which regress the bilateral exchange rates between middle-income countries’ currencies and U.S. dollar against their capital flows.
The empirical results turn out that, as a whole, the capital flows of lower-middle-income countries have both higher explanatory power and better significance toward the bilateral exchange rates than those of upper-middle-income countries. Additionally, the fact that risk proxies have more influence on lower-middle-income countries over upper-middle-income countries, is consistent with the presumption which assumes there is a larger risk difference between lower-middle-income countries’ currencies and U.S. dollar, suggesting that the decision of exchange rates is not only consist of interest rate or/and purchasing power, but also the level of country risk among the international capital market.

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