Multiple studies conducted in the United States, Canada, Germany, and the United Kingdom show that the probability of dying in the hospital is higher if you are admitted on the weekend. Why might this...

Multiple studies conducted in the United States, Canada, Germany, and the United Kingdom show that the probability of dying in the hospital is higher if you are admitted on the weekend. Why might this be? What factors might contribute to this probability?  What could hospitals do to reduce/eliminate this phenomenon?