志愿者的无偿服务，对医院来说，是实实在在的“成本利器”。虽然具体财务数据未公开，但我们可以通过服务时间，大致算出它的价值：
"Often, it's difficult to know if that's related to the injection, or whether they had them originally but weren't assessed properly beforehand."
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all branches had one. Long-distance computer communication links were very
哈克特說，這種自願式調查容易受到「虛假受訪者」影響，使數據失真：「而且這不是隨機的。失真往往在年輕族群中最高。」