It is a myth that people have seven careers in their lifetime

I was surprised the other day to hear a knowledgeable person repeat the old saw that "the typical person has seven careers in their lifetime." Here's a 2010 Wall Street Journal article saying what we all knew - it's not true: 

Do Americans really go through careers like they do cars or refrigerators? 

As workers take in the latest round of monthly unemployment data over Labor Day weekend, Americans are focused on volatility in the job market. Much of what they hear points to growing job instability and increased autonomy of workers. Among the most-repeated claims is that the average U.S. worker will have many careers—seven is the most widely cited number—in his or her lifetime. 

Jobs researchers say the basis of the number is a mystery. "Seven careers per person sounds utterly implausible to me," says Ann Stevens, professor and chair of the economics department at the University of California, Davis.

Here's the Bureau of Labor Statistics:

Does BLS have information on the number of times people change careers in their lives? 

The Bureau of Labor Statistics (BLS) never has attempted to estimate the number of times people change careers in the course of their working lives. The reason we have not produced such estimates is that no consensus has emerged on what constitutes a career change. A few examples may help to illustrate the difficulty of defining careers and career changes. Take the case of a BLS economist who is promoted to a management position. Before the promotion, she spent most of her time conducting economic research. After the promotion to the management position, she still may conduct research, but she also spends much more time supervising staff and reviewing their research, managing her program's finances, and attending to a variety of other management tasks. This promotion represents an occupational change from economist to manager, but does it also represent a career change? It depends on how you define a career change. 

Did a construction worker who decided to start his own home-remodeling business experience a career change? What about a newspaper reporter who became a TV news anchor? Each of these examples involves a change in occupation, industry, or both, but do they represent career changes? Most people probably would agree that a medical doctor who quits to become a comedian experienced a career change, but most "career changes" probably are not so dramatic. 

What about the case of a web site designer who was laid off from a job, worked for six months for a lawn-care service, and then found a new job as a web site designer? Might that example constitute two career changes? If not, why not? Is spending six months at the lawn-care service long enough to consider that a career? How long must one stay in a particular line of work before it can be called a career? 

Until a consensus emerges among economists, sociologists, career-guidance professionals, and other labor market observers about the appropriate criteria that should be used for defining careers and career changes, BLS and other statistical organizations will not be able to produce estimates on the number of times people change careers in their lives.

 Short answer: it's not true.