Data show that the average tenure of a CEO has dropped from 10 years to 8.4 years since 2000.
Data show that the average tenure of a CEO has dropped from 10 years to 8.4 years since 2000. - 

With the disappointing JCPenney earnings today, some are already calling for the ouster of new-ish CEO Ron Johnson. The former Apple retail chief was brought in to revamp the brand and improve sales -- so far, with little success.

For shareholders and corporate boards in various industries, patience with CEOs might be wearing thinner. Data show that the average tenure of a CEO has dropped from 10 years to 8.4 years since 2000.

Tom Saporito is the CEO of RHR International -- it's a firm of psychologists and consultants who work closely with top executives. He joins us now in today's mid-day extra.

Follow Jeremy Hobson at @jeremyhobson