Test scores are often used as a yardstick to measure students' academic progress.

yardstick 是名词，由 yard（码，长度单位）和 stick（棍棒）组成，字面意思是"码尺"，引申为"衡量标准"或"评判尺度"。这个词源于用码尺作为测量工具的传统，现在多用于比喻意义，指用来评估或比较的标准。