Agreed. However, a policy tool is not disqualified merely because it is based on an arbitrary measurement. That's all that needs to be said.
As I've already stated, there are arbitrary measures in public policy. But that is not all that needs to be said simply because you wish to conclude at that thought.
First, stating that some policy is based on arbitrary measures does not mean that all policy should be. Second, it also does not mean that arbitrary measures are all equally useful, comparable or valid. Third, it's also worth remembering that the world is not bisected into the arbitrary and non-arbitrary. There are degrees of usefulness when it comes to arbitrary measures.
It need not. The measure could take into account things like age, ethnicity, gender, etc. In other words, try to back out any non-lifestyle factors, as lifestyle is what you're trying to create incentive to change.
Again, your suggestion indicates that there is no standard or clear attributes for fitness, and as a result, no definition. You are presuming that any set of assumptions of what fitness is are natural. That is incorrect.
Additionally, are there set standards of fitness for every single ethnicity, gender, age group and lifestyle? No. None. Besides, how would you go about calculating the fitness of a woman of one mixed ethnicity and a certain lifestyle and a man of another mixed ethnicity and race, and his own specific lifestyle? Do you have clear and complete health knowledge concerning differences between all genders, ethnicities and age groups? Do have similar knowledge that pertains to every known 'lifestyle' that people engage in? You don't; no one has such knowledge.
As for incentive to change,
change to what? You still have not defined what fitness is.
It seems to me that it should be based on criteria that are significant risk factors in the most common and resource-taxing diseases requiring treatment, including heart disease/stroke, lung cancer, diabetes, etc.
Your point is not clear here. If you are suggesting that fitness be related to the appearance of disease in a person, then you should know all the possible root causes of these diseases first. Smoking increases the risk for lung cancer, but there are still a very large number of people who get lung cancer who never smoked. There are also smokers who never get lung cancer (the majority). People can lead what is presumed to be very healthy lives and still suffer from any one of the above afflictions.
This is an issue for all public policy, and not anything specific to this issue. Immigration comes to mind, and that is higher stakes than a tax credit.
This has nothing to do with immigration. You are attempting to label the entire population with an arbitrary measure for taxation and for exiting school. If your policy is to be so universal, you had better define fitness in clear details, and recognize that the choice of details is always arbitrary, incomplete and subject to change. Furthermore, you would be attempting to legislate the quality of human bodies - and people's lives. The comparison to EI is completely invalid.
Oh, I don't think Hydrogen would like that line of reasoning. Trans fat is a naturally occurring part of our diet. The fact that so much of the trans fat in our diets is 'artificial' (due to processing techniques) is moot.
More confused thinking on your part. Remember, I was the one who informed you that everything is toxic in large enough quantities. That's literally the first rule of ecotoxicology.
You still have failed to define what fitness is, and you also have neglected to state who you would see doing all this policing over the bodies of people. Rather than to presume to answer for others, try describe how you would regulate and police the bodies of the entire population.
