本研究意在探討一位國中國文教師在教學評量上的實踐知識，包括評量實踐的運思歷程，以及如何促進學生學習的評量策略之運用。我們採個案研究取向，進入教室觀察，輔以訪談、文件蒐集等策略。歷經一個學年的現場參與，分析歸納出教師的評量意象為「長高」－提升學生的學習能力，其下攝三個教學評量目的：1.增高：評量作為主食，與教學內容結合以促進學習，且依其與教材相關程度，實施習作、應用練習等，如同吃飯對於身高增進的作用一般，另外也有其他輔助活動如翻翻書、聯絡簿生活札記等，如同吃菜增加營養般來增進身高。2. 助高：評量作為調味，增加學習趣味，強調參與過程並藉活動維持學習動力，如背書競賽、圖畫課文等。3. 量高：評量作為刻度以瞭解學習成果，穩定教學進程，如小考、段考等。個案老師適當調配「促進學生學習」（增高）、「增加學習趣味」、（助高）以及「瞭解學習成果」（量高）三個評量的目的達成學生能力長高的任務。文末研究者進一步提出關於意象隱喻、個人風格、與考試評量的啟示。

This study was to investigate a junior high school teacher's practical knowledge on classroom assessment, particularly aiming on rationality and strategies. Case study was adopted. Data were collected from classroom observations, interviews, and documents during one-year fieldwork. The image of growing tall was concluded as a theme that serves three objectives in classroom assessment: 1. As main meals to increase height: to improve learning as a source of energy. Assessment is part of instruction. Main dishes and side dishes serve as textbooks materials and related activities 2. As seasonings to stimulate growing: to raise students' interest of learning. Learning process and participation were emphasized than assessment results. 3, As a scale to measure the height: Assessment was utilized to diagnose and monitor learning results. The case teacher balanced out the three roles of classroom assessment: to improve learning, to increase learning interests, and to monitor learning results, with a purpose to guide students growing tall on ability, which was the core content of the case teacher's practical knowledge on classroom assessment.