在新藥的療效研發過程，第二期臨床試驗主要在了解藥品的有效性與安全性，進而決定給藥的方式、劑量等，作為是否進入第三期臨床試驗的依據。基於人道立場考量和保障參與者健康的前提下，應避免參與者長期處於無療效或副作用過高的療程中。因此，其目的在於減少療程時間、縮短招募參與者等候時間的兩階段試驗設計就此誕生。
Buzaianu 和 Chen 於 2009 年提出縮減混合選擇與檢定程序(A Hybrid Selection and Testing Procedure with Curtailment)。以 Thall 等人於 1988 年提出的兩階段選擇與檢定設計(Two-Stage Selection and Testing Designs)為出發點，進行縮減與逐次檢定。此設計的最大優點是一旦有足夠的證據說明新藥的有效性時，即可提早終止招募病人，制定決策。本論文延續 Buzaianu 和 Chen 所提出的觀念，發展出使用範圍更廣泛的兩階段縮減設計。針對大多數可能的情況進行數值模擬計算，並與 Thall 等人的兩階段選擇和檢定設計、Dunnett 於 1984 年提出的單一階段選擇程序(A Single-Stage Selection Procedure)進行比較。最後透過模擬結果說明兩階段縮減設計具有較佳的效能表現。

Buzaianu and Chen (2009) proposed strong curtailment to test several experimental treatments against a control for selecting the best treatment among several Bernoulli treatments. The curtailment procedure is based on the concept of sequential test and the fixed sample size selection and testing procedure proposed by Thall et al. (1988).
In this thesis, the modified curtailment procedure was proposed while the responses not only were binary measurements, but also were ordinal or continuous measurements. A detailed numerical results of expected sample size also were calculated in a wide variety of situations and compared with original fixed sample size procedure of Thall et al. (1988) and single-stage selection procedure of Dunnett (1984). The results showed that the proposed two-stage curtailment procedure performed much better than the non-curtailment procedure of Thall et al. (1988) and the single-stage selection procedure of Dunnett (1984).

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