The three most common variations of Fitts’ index of difficulty are the Fitts formulation, the Welford formulation, and the Shannon formulation. A recent paper by Hoffmann [1] critiqued the three and concluded that th...The three most common variations of Fitts’ index of difficulty are the Fitts formulation, the Welford formulation, and the Shannon formulation. A recent paper by Hoffmann [1] critiqued the three and concluded that the Fitts and Welford formulations are valid and that the Shannon formulation is invalid. In this paper, we challenge Hoffmann’s position regarding the Shannon formulation. It is argued that the issue of validity vs. invalidity is ill-conceived, given that Fitts’ law is a “model by analogy” with no basis in human motor control. The relevant questions are of utility: Does a model work? How well? Is it useful? Where alternative formulations exist, they may be critiqued and compared for strengths and weaknesses, but validity is an irrelevant construct. In a reanalysis of data from Fitts’ law experiments, models built using the Shannon formulation are (re)affirmed to be as good as, and generally better than, those built using the Fitts or Welford formulation.展开更多
为了使研究人员能够快速、有效对手持设备的三维菜单设计进行评估,基于Fitts’定律和Hick-Hyman定律,提出了一个预测手持设备三维菜单操作绩效的模型,并用实验验证了该模型的有效性。实验分为两个阶段,第一阶段的实验是为了计算模型中...为了使研究人员能够快速、有效对手持设备的三维菜单设计进行评估,基于Fitts’定律和Hick-Hyman定律,提出了一个预测手持设备三维菜单操作绩效的模型,并用实验验证了该模型的有效性。实验分为两个阶段,第一阶段的实验是为了计算模型中的系数a1,b1,a2,b2的值,并将其用于实验第二阶段的数据分析;第二阶段的实验是为了验证模型的有效性。并结合AIC(Akaike Information Criterion)准则对该模型与其他模型进行了对比分析。实验结果表明,该模型预测得到的用户操作绩效数据与实验测试得到的绩效数据非常接近(二者相关性为0.9145),且通过AIC准则分析表明,该模型最优。因此,该模型是有效的。展开更多
文摘The three most common variations of Fitts’ index of difficulty are the Fitts formulation, the Welford formulation, and the Shannon formulation. A recent paper by Hoffmann [1] critiqued the three and concluded that the Fitts and Welford formulations are valid and that the Shannon formulation is invalid. In this paper, we challenge Hoffmann’s position regarding the Shannon formulation. It is argued that the issue of validity vs. invalidity is ill-conceived, given that Fitts’ law is a “model by analogy” with no basis in human motor control. The relevant questions are of utility: Does a model work? How well? Is it useful? Where alternative formulations exist, they may be critiqued and compared for strengths and weaknesses, but validity is an irrelevant construct. In a reanalysis of data from Fitts’ law experiments, models built using the Shannon formulation are (re)affirmed to be as good as, and generally better than, those built using the Fitts or Welford formulation.
文摘为了使研究人员能够快速、有效对手持设备的三维菜单设计进行评估,基于Fitts’定律和Hick-Hyman定律,提出了一个预测手持设备三维菜单操作绩效的模型,并用实验验证了该模型的有效性。实验分为两个阶段,第一阶段的实验是为了计算模型中的系数a1,b1,a2,b2的值,并将其用于实验第二阶段的数据分析;第二阶段的实验是为了验证模型的有效性。并结合AIC(Akaike Information Criterion)准则对该模型与其他模型进行了对比分析。实验结果表明,该模型预测得到的用户操作绩效数据与实验测试得到的绩效数据非常接近(二者相关性为0.9145),且通过AIC准则分析表明,该模型最优。因此,该模型是有效的。
