Just out of high school, John Smith can't decide whether to go to college. If he does, according to US Census Bureau statistics just published for the first time, he will increase his lifetime earning power 40 percent. If he takes the college route he should expect lifetime earnings of $1.9 million to $2.75 million. Without college, he can expect $860,000 to $1.87 million.
If his sister Sue chooses college, the results will be different. Analysts estimate that for her adult working life (from 18 to 64) she'll earn $520,000 to ,000.
The new Census Bureau projections are based on data from 1978, '79, and '80, and broken down for age, sex, and education. Lifetime earnings estimates often emerge in lawsuits over losses of workers' potential worth. High school counselors use statistics on pay differentials in advising graduates.
Is there sex discrimination here? Not necessarily, says Bruce Chapman, census director: Their lifetime work habits are different. To begin with, says John F. Coder of the Census Bureau, figures of lifetime earnings are ''somewhat speculative in nature'' and work patterns differ.
Feminist Betty Friedan says women are hardly more than ''halfway down the road'' to equality. But Phyllis Schlafly, who led opposition to the proposed Equal Rights Amendment, stresses difference in work careers. She says that the average woman has been in her job only half as long as the average man.
Meanwhile, in Washington, the biggest immediate argument over workers' pay involves retirement. The House has just voted to raise the social security retirement age from 65 to 67. The change is widely backed for two reasons: The social security system is running out of money and will save by requiring later retirement; and Americans now live longer than they did when the system began 50 years ago. Half a century from now, say actuaries, the present 65-year-old will have a life expectancy of 17 more years, compared with 14.5 years today.
There's a third big work argument going on over the minimum wage.
In 1938 Congress set the original minimum wage at 25 cents an hour. For untrained workers, often young people, the legal start-off pay has gradually risen. Currently, teen-age unemployment is around 22.2 percent, 45.7 percent for black teen-agers.
President Reagan wants to lower the minimum wage rate to give more jobs to youngsters and others. Trade union spokesmen oppose the move; they say it would punch holes in their wage protection. On March 11 Mr. Reagan proposed to cut the minimum wage for youth to $2.50 from May 1-Sept. 30 each year. Labor Secretary Raymond Donovan says the change would help to attack ''this national tragedy.'' In the last Congress, some 21 bills to cut the minimum wage were introduced. Few think they have much chance. Reagan himself agreed last month that it would be ''hopeless,'' but he has pushed the plan for years.