Jacob Hacker , a Yale University political scientist , found that the income of the average family was about twice as volatile in 2000 as it was in the 1970 's -- a result of rising health and education costs , the increasing rate at which people change jobs and the shift from pensions with guaranteed benefits to 401 -LRB- k -RRB- 's .
Jacob Hacker /business/person/company Yale University
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