合理的法定工時是多數勞工的期待，在法定工時縮減的同時，世界各國卻不乏從事雙份工作的勞工。此現象在經濟學稱為月光現象(moonlighting phenomenon)，意謂勞工白天從事主要工作，晚上另從事第二份工作的披星戴月之意。長期以來，台灣工時名列世界各國前茅，高工時可能會壓縮勞工從事兩份工作的空間。但當法定工時逐漸降低且加班規定又變嚴格時，該空間已然變大。那麼，台灣自2001年以來已進行的法定工時的調降是否導致了月光效果呢? 本計畫擬以實施勞動基準法至第二次修改工時規定之前的期間，即1984年至2016年「人力運用調查」共33年的原始資料，採difference-in-difference的方法，以probit model探討2001年實施法定工時縮減對勞工第二份工作意願之影響。並以bivariate probit model控制加班意願的考量，分析該變革的月光效果。同時，本研究也擬探討工時縮減對哪些特質勞工、哪些行業或職業勞工具有較大的月光效果，藉此了解月光效果的差異與成因。由於勞動市場對於勞工擁有多元技術的需求逐漸加強，透過第二份工作獲得第二專長的需求可能提高之外，實質薪資之停滯對此決策亦可能具有推波助瀾之效。因此，不論是基於經濟或非經濟因素，台灣勞工接受第二份工作的意願應該已不可同日而語。本計畫的研究結果應可作為台灣工時調整之參考，並可據此提出相關的政策建議。 ;Workers are normally expecting reasonable statutory working hours. Along with the reduction in statutory hours, a certain proportion of workers are however dual job holders. It is the so-called moonlighting phenomenon, meaning people working in the main job during the day and doing a second job at night. Taiwan has long been ranked top among the world's longest working hours. A higher working time could more or less compress the space for workers to work in two jobs. However, since 2001, Taiwan has changed the statutory working hours twice. Because the statutory hours have been reduced nowadays and the overtime regulations become stricter, the room for holding second job could have been increased. It is thus wondering whether the change in statutory working hours in Taiwan lead to moonlight effects?In this project, the “Manpower Utilization Survey”1984 to 2016 data will be used for empirical analysis, a time period between the launch of the Labor Standard Law and the second reduction in statutory working hours. The difference-in-difference methodology is employed, along with probit model specification, aiming to investigate the impact of statutory working hour reduction on people’s willingness of holding dual job. In addition, we will use a bivariate probit model to account for the overtime effect so as to obtain consistent estimation results. Moreover, differences in the moonlight effect among workers of various characteristics such as educational level, occupations and industry, will also be analyzed which help exposit the causes of moonlighting. It is noticed that multi-skilled is the demand tendency in the labor market. Holding a second job might assist people gain second expertise. The stagnancy in real wages might further contribute to the plausibility of holding dual jobs. As a consequence, based on economic and non-economic considerations, the willingness of Taiwanese workers to accept a second job should no longer be the same as before. The findings of this study can be used as a reference for the policy of working hour in Taiwan, and can be put forward to relevant policy suggestions accordingly.
