It is a brutal management technique in which bosses grade their employees’ performance along a “vitality curve” and sack those who fall into the lowest category. Known as “ranking and yanking”, it had its heyday in the 1980s and 1990s. In America its popularity faded somewhat after it was seen to have contributed to the fall of Enron. Now it is back in the headlines.  Mayer: who’s for the chop next?   Employee Atmosphere Yahoo Style