A good idea to be brought out

When studing the Rasch model in designing scale, a wonderful idea was yielded.
Why we cannot design a scale for evaluating someone's ability about that using chopsticks.
Dr. Roberto was told to learn using chopstick in Taiwan. After practising it over many weeks and knowing it very well. \
Why we do not design a scale in evaluating abilities of persons and comparing it as well as obtaining a logit value of that ability level to reveal the result of practising chopstick in Taiwan.
That is also said that what is the performance of using chopstick by Dr. Roberto, which can be evaluated and brought back to tell his father what is the level of the performance. That is not only said I have known it. The amount of that performance results should be qualitified.