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JianchuanUID: 2121431

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elvazhang1022UID: 208363

In this argument, the speaker asserts that taking twice the recommended dose of vitamin D and calcium daily is the most effective way to reduce the risk of fractures. To justify his / her statement, the author of this argument（我认为可以省略） provides us with a survey on French women. However, this argument is relied on an unwarranted basis and an ill-conducted survey, which close scrutiny reveals heavily flawed. Therefore this recommendation is not well justified and unconvincing.

To begin with, this argument is based on the assumption that as people age, their bone mass decreases, making them more vulnerable to bone fractures. The arguer fails to predict other possible causes of fractures, for instance, traffic accidents, falling from high places. In these scenarios, no matter how strong the victims are, it is equally possible for everybody to get fractured. Thus, the basis of this argument is flawed.

In the second place, the survey is not sufficient to conclude the arguer's recommendation. The sample is not even representative for all the cases fractures related to. As all we have known, France is a well-developed country, where people enjoy higher living standard than average. Thus, the arguer ignores the possibility that those French women are initially healthier than other women and less inclined to have fractures. To justify this study, the researchers should choose ample samples from well-defined groups, from the healthiest to the weakest.

The survey mentioned in this argument is also flawed from another respect that the French women showed a much lower rate of hip fractures than average is quite possible because of the weightlifting program and totally has nothing to do with the doubled dose of vitamin D and calcium（这句话太长了，建议作者先断句，这样比较容易发现结构上的错误）. To rule out this possible explanation of the low fractures rate, the control group should also attend the weightlifting program or neither of the two does. Moreover, the time range of this study（总觉得这样说不是很顺，the range of time the study covers会不会好点？） is relatively short, for most normal people will not get fractured in such a short time period.

It is also necessary to point out a lower rate of hip fractures is little indication of lower overall fracture rate. The author of this argument obviously falsely equates hip fractures with all kinds of fractures. It is entirely possible that those French old ladies suffer more fractures of other kinds, which the argument avoids to mention. Or it is quite likely that the overall fracture rate in aged women is all the same.

So, in conclusion, the argument is based on an ill-conducted study and therefore is not well supported. To justify this recommendation, the arguer should better conduct this study again, with representative sample, and a longer observing time period. Also he should not allow his sample to attend health-related programs if the averages do not. To better assess the argument, I also need information about the frequency of fractures due to bone mass decreasing and that of all fractures.


还可以攻击的点：
1.还是样本的问题：既然是研究the risk of fractures in later life，那么只研究women in their eighties是不科学的，结果推广性不强；
2.即使承认to take twice the recommended dose of vitamin D and calcium daily对减少骨折是有效的，也不能说这就是最有效的方法，因为缺乏同其他方法的比较