LOS ANGELES - "Once a liar, always a liar" is a proverbial parental admonishment.

A national study claims there is truth to the adage: People who cheated on exams in high school are considerably more likely to be dishonest later in life, said a report to be released today by the Josephson Institute of Ethics.

The study, which surveyed nearly 7,000 people in various age groups, offers a sobering assessment of today's youth as cynics who are aware their behavior crosses boundaries but believe it is necessary to succeed. And the findings suggest habits formed in childhood persist: Those who cheated in high school are more likely as adults to lie to a customer, inflate an insurance or expense claim, cheat on taxes and lie to their spouse.

"When you see that teens are five times more likely than adults to think it's OK to cheat to get ahead, we have a problem," said Rich Jarc, executive director of the Los Angeles-based Josephson Institute. "Just think if five times the number of people in business, politics and banking hold those beliefs. That's alarming."

The study found teens 17 and younger are five times more likely than those older than 50 to believe lying and cheating are necessary to succeed.

The Josephson Institute issues biennial reports on the ethics of American high school students that have charted a steady increase in those admitting to cheating, lying and stealing. The new study is the first known to connect teen behavior to dishonest activities in adulthood.