在儲訓校長的培訓課程中，即席演講為重要的培育能力之一。過去在進行演講評分，大多使用所有評審分數的加總或是平均當作最終的分數，然而，當比賽的人數眾多必須分組時，每一組評審的嚴苛度可能會對成績造成影響。本研究將評分項目、評分委員的嚴苛度放進多層面Rasch模型中估計，進而以較為客觀的方式來評估儲訓校長的口語表達能力。研究結果發現，即使有受過訓練的評分者，在評分過程中，還是有嚴苛度的不同，而儲訓校長在演說上，對於內容、架構，語詞使用、與時間掌控等部份較感困難，而對於發音標準、演說中有合適的語調，具有良好的儀表態度等向度感到較為容易。此外，若忽視納入可能影響的層面而直接使用原始分數總分或是平均做為受試者的成績，可能會造成分數上的誤差與排名的不公。

In the pre-service training program, impromptu speech is one of the most important ability to develop for school principals. To assess the speech ability, most researchers use the total or average of the raw scores as final scores. However, when there are many students attending the test, raters need to be divided into several groups to provide grading, and the severity of the raters for different groups may impact students' score. In this study, the scoring criteria, rater's severity and person's ability are all considered into the multifaceted Rasch model. The results show that, even for the trained raters, there still exist subjectivity and different level of rater severity. On the other hand, school principals feel most difficult in content, framework, proper usage of words and time control and feel relative easy in pronunciation, prosody, and appropriate manner in the context of impromptu speech. The ignorance of facets and use the raw total or average score as final score may cause bias or unfairness of the score ranking.