本研究旨在探討企業處在不同的生命週期階段時，資本市場對於各期的研究發展支出會有不同的評價。本文援引Anthony and Ramesh (1992)的方法，選定股利、銷貨成長、資本支出與公司成立年數為生命週期的判斷因子。本文使用Ohlson (1995)的會計評價模式，以盈餘、市值、資本支出與研究發展支出，設定為迴歸模型檢驗生命週期係數差異假說。實證結果發現，研究發展支出與股價之間呈現顯著的正向關係，當進一步考慮不同的生命週期階段時，發現在成長期的研發支出，對於股價的影響顯著大於成熟期及衰退期。此外，成長期的資本支出，對於股價的攸關性也顯著大於成熟期及衰退期。進一步發現，在成長期研究發展支出的反應係數顯著大於資本支出，在衰退期則否，因此實證結果支持研究假說：研發支出與資本支出二者相對應的反應係數的差異幅度，也會隨著生命週期而有不同。

The objective of this paper is to investigate whether market response to research and development expense (hereafter R&D) varies across firms' life cycle stages. We hypothesize that response coefficients of firms' R&D decrease from the growth to the stagnant portfolios. We divided samples into various life cycle portfolios based on methods developed by Anthony and Ramesh (1992). Consistent with our hypothesis, we documents that, like capital expenditure, a monotonic decline in the response coefficients of R&D cost from the growth to the stagnant stages. Furthermore, the findings also support the notion that the response coefficients of R&D are significantly greater than those of capital expenditures at the stage of growth compared to the stage of stagnant. Finally, we also find that difference in the coefficients between R&D and capital expenditures decreases from the growth stages to the stagnant stages. These findings are robust to control for size and risk effects.