This newspaper has been worrying out loud for much of the last two decades about the human and economic costs of too many young people dropping out of high school.

For much of that time, economic growth masked some of the impact. But the Great Recession put an end to all that. Now, as the U.S. job market shows some weak indications of recovering, the Wall Street Journal pointed out Tuesday, "one sizable group of workers has been falling further behind: high school dropouts."

At a time when the economy and companies are demanding more education and higher skills, less than 40 percent of the 25 million Americans over age 25 who lack a high school diploma are employed, the Journal reported. High school dropouts earn an average of about $23,400 compared to $33,500 for those with a diploma. Four-year college graduates earn an average of $54,700, according to Bureau of Labor Statistics data quoted by the Journal.

Meanwhile, "the gap is expected to widen," the Journal said, quoting a McKinsey Global Institute Study that found that by 2020 there will be 6 million more high school dropouts than there are jobs available to them. At the same time, the Journal said, there will be a shortage of about 1.5 million college-educated workers.

"High-school dropouts are being left futher and further behind," McKinsey researcher Susan Lund told the Journal.

There was a time when employment in small family businesses allowed the less skilled an opportunity to obtain skills and advance. But as expensive technology has played a larger role across a variety of businesses, companies are demanding that workers have a high school equavalency test -- the GED -- at a minimum to get hired. Even if workers manage to pass the test and get a job, wage levels remain depressed for many positions.

Immigration of low-skilled workers has only added to the challenge.

The most obvious -- but by no means easy -- solution is to dramatically reduce the dropout level, especially in high-cost, high-tech economies like California's.

The second solution -- again, in no way an easy one -- is to get more students to college or technical training.

It took decades and the Great Recession to create this employment failure. It will take many years to correct it, but correct it we must.