Our MPs are now less likely to come from traditional careers in business and unions and are more likely to be "generalists" who turn to politics as a career.
Political researcher Geoffrey Miller and public relations expert Mark Blackham researched the histories of all 121 members of the current Parliament.
They found that business owners, agriculturalists and unionists have a falling share of the voice within their parties.
They've been replaced by people with no specific career interests, or careers limited to government and politics.
"National is no longer dominated by business experience and Labour no longer by unions," the researchers said.
"In fact, the whole of Parliament is now dominated by generalists, people of no specific experience, and government specialists - people whose only experience is working for government or in politics."
They say that while the battles in Parliament are still talked about as business versus unions, MPs actually have little experience in these fields.
The single most common career in Parliament is in business (19 MPs) but they're outweighed by those with no single career (23 MPs) and those with careers in government or political organisations (15 MPs).
Ten MPs are career politicians, with no work experience outside of Parliament.
"Politicians portray themselves as ordinary people, but our findings show many of them are anything but," the researchers said.
"Across the spectrum, previous work experience for many new MPs increasingly consists of working for a political party in Wellington, in a role funded by the taxpayer."
They conclude that Parliament is reflecting something ordinary people are experiencing - the tendency to go through a range of jobs rather than a single career.