If one ambition for your children is to see them join the 1 percent, you might want to re-evaluate their career paths.

Here are a few pointers: End the search for the summer “internship.” Stop obsessing with getting them into an Ivy League institution. Recognize that all roads don’t lead down Wall Street.

Instead, insist that they get a part-time job while in high school, receive a good education from a state university, and recognize the value of owning a porta-potty company while living in the Midwest. So says an expert who has spent three decades studying the affluent.

Fifteen years ago, Thomas Stanley and William Danko published “The Millionaire Next Door: The Surprising Secrets of America’s Wealthy.” It was an instant best-seller, and today, there are more than 2 million copies in print. According to one of the authors, with whom I recently spoke, the lessons of the book hold firm, including that the identity of the person in your neighborhood with the highest net worth could come as a surprise. It might not be the private equity trader down the street. Or the doctor or lawyer up the block.

“The consistent finding that I have had for the last 30 years is that most who are wealthy are business owners, often of blue-collar businesses, that most others have ignored,” Stanley told me.

Think janitorial. Or scrap metal (now “recycling”). And dry cleaning, especially the industrial variety. It’s the successful owners and operators of such unglamorous businesses who have often been able to make money in one generation.

Stanley told me that these entrepreneurs tend to be more frugal than others of the same age and income. For example, his research shows that they typically live in areas where they have “five, 10, or 25 times more wealth than their neighbors.” The median value of their homes? In the “low to mid-$400,000 range.”

Many of us envision Mitt Romney when we think of getting rich in America — wealthy parents, Harvard degrees, partner in a Boston-based financial business, residences in Wolfeboro, N.H., and La Jolla, Calif.

But the more common path is a guy who sold Christmas cards door-to-door and flipped burgers as a kid, received a public school education, and now runs a scrap yard in Missouri.

But here’s the kicker.

That millionaire next door now has children who have enjoyed the fruits of his labor. Whereas mom and dad received a public education, the children are privately educated. They are the ones who get to go to Ivy League schools, and when they graduate, they have little inclination to step into the family business that paved their way. So where do they end up?

The hardest part for millionaires, it seems, is passing on the lessons of financial success.

• Smerconish writes for The Philadelphia Inquirer.