The Washington Post reports: As the board of Amgen convened at the company’s headquarters in March, chief executive Kevin W. Sharer seemed an unlikely candidate for a raise.

Shareholders at the company, one of the nation’s largest biotech firms, had lost 3 percent on their investment in 2010 and 7 percent over the past five years. The company had been forced to close or shrink plants, trimming the workforce from 20,100 to 17,400. And Sharer, a 63-year-old former Navy engineer, was already earning lots of money — about $15 million in the previous year, plus such perks as two corporate jets.

The board decided to give Sharer more. It boosted his compensation to $21 million annually, a 37 percent increase, according to the company reports.

Why?

The company board agreed to pay Sharer more than most chief executives in the industry — with a compensation “value closer to the 75th percentile of the peer group,” according to a 2011 regulatory filing.

This is how it’s done in corporate America. At Amgen and at the vast majority of large U.S. companies, boards aim to pay their executives at levels equal to or above the median for executives at similar companies.

The idea behind setting executive pay this way, known as “peer benchmarking,” is to keep talented bosses from leaving.

But the practice has long been controversial because, as critics have pointed out, if every company tries to keep up with or exceed the median pay for executives, executive compensation will spiral upward, regardless of performance. Few if any corporate boards consider their executive teams to be below average, so the result has become known as the “Lake Wobegon” effect.