论文专业
Index of difficulty
难度指数（ID），Fitts' 定律中的核心变量，定义为 log₂(D/W + 1)，其中 D 为到目标的距离，W 为目标宽度。
English Definition
"In Fitts' Law, a measure of the inherent difficulty of a pointing task, calculated as log2(D/W + 1), where D is distance to the target and W is target width."
用法说明 · 针对中文母语者
常用缩写 ID，注意与 Fitts' Law 配合使用。中文文献中常保留英文术语或译为「难度指数」。
真实用例 · 2 条
"Participants completed 1D pointing tasks under different latency conditions, uncovering a linear effect of latency on task time and thereby the task's index of difficulty."
论文Pipeline extracted — review needed·MacKenzie & Ware 经典研究中揭示 latency 对 ID 的线性影响
"A delay of 100 ms already leads to a 50% increase of task difficulty for moving targets, and increases even more when targets are moving faster."
论文Pipeline extracted — review needed·延伸讨论中用 task difficulty 描述难度变化
由 pipeline 自动采集，待人工 review