The following appeared in a memo from the director of a large group of hospitals."In a laboratory study of liquid antibacterial hand soaps, a concentrated solution of UltraClean produced a 40 percent greater reduction in the bacteria population than did t

The director concluded that the hospitals should supply UltraClean soap hand-washing stations throughout the hospital system. However that conclusion partly based on the assumptions which are unwarranted and unstated. The whole argument ought to consider evidence more carefully.

The author stated that a concentrated solution of UltraClean produced a 40 percent greater reduction in the bacteria population than did the liquid hand soaps currently used in our hospital. This statement suggests that the concentrated soap is effective in any situations including the Workby and the whole hospital. But in fact the conclusion is drawn in a laboratory study when there are no other factors to affect the result of it. If it were supplied to all the hospitals the effect might be worse. It may be true that the concentrated soap could reduce the number of bacteria but the real effect may not be so well. And then we should take into consideration of the all the conditions in hospital.

The assumption that concentrated soap is more effective than regular one is partly base on the fact that hospital reported significantly fewer cases of patient infection than did any of the other hospitals in our group. The director obviously overlooks the possibility that the hospital did the test may possess less patients than any other hospitals, then whether the concentrated soap is more or less effective will not be correctly tested. Then we have to consider the evidence that the visitors may hate to use concentrated soap because its smell is too strong or bad. The effect of it thus can not be concluded and the director must take a survey on how much people love the new soap, then decide if he would apply it to all the hospitals. The additional evidence that the bacteria which may have the highest possibility to infect the patient might be lower when concentrated soap is applied to the hospital may weaken the argument. The concentrated soap consequently only kills those fragile bacteria.

In summary, the conclusion that concentrated soap should be used in all the hospitals is not sufficiently supplied. The director did not think about the fact that the bacteria killed are not the one which most likely infected the patients, the smell of the concentrated soap, and the number of patients in other hospitals.