What's the probability of a good drug launch? About one in three, according to a new McKinsey & Co. analysis. And if a launch is good, it tends to be very, very good, beating forecasts year after year. That means two-thirds of drug launches fall short of expectations. And once a drug launch goes bad, it stays bad. Fortunately, says McKinsey, a sharp analysis of the product and its market can start things off on the right track. Story