臺灣主要年齡層25-54歲之男性勞動參與率與就業比率，自1994年的97％及96％左右，分別下降至2002年的93％及88％，本文試圖從人口、市場機會及參與行為來探討勞動市場福祉惡化之原因。研究結果發現1994年以前，此年齡層民間人口快速增加，在市場機會大幅增加下，吸納了大多數民間人口的成長；1994年之後，雖然民間人口增加速度減緩，然市場機會之增加幅度卻大幅下降，參與行為亦下降，造成勞動參與率與就業比率的下滑；其中又以國中小以下學歷者最為嚴重，該族群之人口數大幅下滑，而市場機會顯著減少，參與的程度下滑。高中高職學歷者之市場機會，在1994年以後無顯著增加，然人口數仍在成長中，其福祉受損之程度，僅次於國中小以下教育程度者。45-54歲者亦是受害之族群，其福祉惡化最大的原因是，此群組之國中小以下學歷者之人口比率遠超過其他年齡層。主要年齡層之男性一旦失業後，大部分仍然在勞動市場尋找工作，然退出勞動市場之比率亦快速增加；一旦退出勞動市場，想工作而未找工作者佔絕大多數。

In Taiwan, males' labor force participation rate (employment rate) had declined from 97% (96%) to 93% (88%) between 1994 and 2002. We investigated the patterns and the causes of this trend against changes in population size, market opportunities, and participation behaviors. We found that, before 1994, the favorable labor market opportunities were successful in absorbing the large increase in prime-aged population. The growth in the labor market opportunities, however, has slowed down since 1994, and was no longer able to catch up with the increases in population size. Both the market opportunities and the labor force participation behaviors had significantly declined for workers with nine years of schooling and below. To a lesser extent, the workers with twelve years of schooling had also suffererd. Prime-aged males who had lost their jobs in most cases chose to remain in the labor force. In the meantime, the proportion of workers out of the labor force grew substantially since 1994.