The popular understanding of what it means to be financially sensible has been shaped by the many books written by Suze Orman, Dave Ramsay, Robert Kiyosaki and others. They're influential, but are they correct.

It's not always the case if you ask an economist. Every entrepreneurial who wants to manage their money rationally a favor and read the top fifty personal finance books according to the consensus opinion from academic economists was compared by a Yale finance professor to the top fifty personal finance books.

The guru did well. While the professors agree with the pundits on a lot of questions, they differ greatly in a few important questions.

Almost all of the personal savings experts agree that you should be saving more. Yesterday was the day you needed to begin. "Of the 45 books that offer some sort of savings advice, 32 stress the importance of starting to save immediately and 31 tell the reader about the power of compound interest." The need for everyone to build an emergency savings buffer is mentioned in 28 books.

It might be surprising to learn that the always save a set amount rule isn't endorsed by economists, given that saving for an emergency is as uncontroversial as it is in personal finance. Academics agree that you should invest in yourself and your joy when you're young and relatively poor, and when you're hoping to make more money.

PhDs in economics can do the math on this one. Most people know that paying off debt with the highest interest rate first will save you money, but many books still advocate another approach.

Dave Ramsey's "snowball method" advises you to pay off the smallest debt first and then move on to the next smallest debt. If you don't win quickly, you will lose steam and get discouraged.

A lot of space is devoted to the question of whether you should go for a fixed rate mortgage or anARM. There is no simple answer to this question with borrowers needing to take into account a number of factors, including the current interest rate, the risk of inflation, and how long you're likely to stay in the home. Gurts are more positive on FRMs than economists.

According to a classic economics model, borrowers should generally prefer ARMs over FRMs.

Maybe you shouldn't beat yourself up if you don't contribute to your IRA when you're 23, and that you should use basic math when choosing which debt to pay off first. The deeper lesson is that popular authors have a better understanding of how humans behave than professors do.

The advice of the Suze Orman's may not be perfect. Taking into account people's quirks is an excellent way to look at them. It doesn't make sense to save 10% of your income straight out of college. From a mathematical point of view, the snowball method is batty but it makes perfect sense.

"Personal-finance best sellers blend theory and psychology in a way that takes human nature seriously, but also warns that those who spend a lifetime delaying gratification may one day find themselves rich in savings but poor in memories."

The overall less for most entrepreneurs is summed up by this. The power of math and psychology is similar. The best personal finance strategy is the one that is closest to the mathematical ideal that you can actually carry out.