許多研究已證實了國家經濟能力與國防預算的關係。然依照預算制度的精神，國防預算規模似乎與軍事戰略及軍事能力密不可分。基此，本研究嘗試釐清軍事防禦能力、國家經濟能力與國防預算的關係。研究中採用階層迴歸方法，依序將軍事防禦能力與國家經濟能力(GDP)納入國防預算模式作為解釋變項。經由167個國家119911到1998年間資料的檢定，研究結果顯示：(1)軍事防禦能力對國防預算規模有著正向的影響關係；(2)當軍事防禦能力變項加入分析模式時，會顯著降低國家經濟力變項對國防預算的解釋力。此實證結果指出經濟能力與軍事防禦能力可能屬於不同層次的分析變項，軍事防禦能力在國家經濟能力與國防預算之間應是扮演中介變項的角色。另外，我們也發現所得越高的國家會傾向擁有較強的軍事防禦力；高所得國家會傾向維持較高比例的海空軍編組結構，而低所得的國家會以陸軍為中心。
Many studies have documented that economic strength (ES) of a state impacts its size of defense budget (DB). However, a close relationship seems to be expected of defense budget, military strategy and military capacity, according to the budget theory. This paper thus aims to clarify the relationship of military defense capability (MDC), ES and DB. We employ the Hierarchical Regression method and use data taken from a sample of 167 countries for the period 1991-1998. Our results show that (1) MDC is positively associated with defense budget size; and (2) the explanatory power of ES on the size of defense budget is significantly reduced when MDC is induced in the budget model. From such evidence, MDC is logically proved to be an intervening variable between the variables ES and DB. In addition, our findings also indicate that countries with higher GNP would tend to maintain higher MDC and that only such countries have the ability to keep a higher share of Navy and Air Force personnel.
