Science and technology are upending how we learn. We separate the science from the snake oil and look at how parents, teachers, and policymakers respond.

Education pays.

According to a new report from the Organisation for Economic Co-operation and Development (OECD), adults with a college degree are 10 percentage points more likely to be employed, and will earn 56% more on average than adults who only completed the end of high school. They are less likely to suffer from depression than their less-educated peers.

The US has always enjoyed a huge advantage in higher-ed attainment. In 2000, 43% of 25-34 year olds had a college education compared to an average of 26% in the 35 OECD member countries. But that advantage is quickly closing. In 2016, it was down to four points, with 48% of Americans following through to higher ed. And Americans now have to compete in an increasingly competitive global workforce.

American teachers lag in salary

According to the report, Education at a Glance 2017, US teachers, on average, earn less than 60% of the salaries of similarly-educated workers. They have among the lowest relative earnings across all OECD countries with data. This is what teachers’ salaries, relative to that of other college-educated adults looks like in 24 of the OECD’s 35 countries:

There is ample evidence that the quality of teachers is the key ingredient to raising educational standards—more than money spent, or class size, or what curriculum is best designed. Pay doesn’t dictate quality, but it certainly influences it.

John Hattie of the University of Melbourne has examined more than 65,000 research papers (1200 meta-analyses) on the effects of hundreds of different educational interventions. He discovered that things we think matter a lot—class size and streaming by ability—don’t matter nearly as much as the quality of a teacher. According to the Economist, “All of the 20 most powerful ways to improve school-time learning identified by the study depended on what a teacher did in the classroom.”

Money and prestige matter. The highest performing education systems always prioritize the quality of teachers says Andreas Schliecher, head of the education directorate at the OECD. “Wherever they have to make a choice between a smaller class and a better teacher, they go for the latter. Rather than putting money into small classes, they invest in competitive teacher salaries, ongoing professional development and a balance in working time.”

US teachers spend 38% more time in front of the classroom than their international peers: 981 hours compared to an OECD average of 712 per year. This is time that they are not collaborating with peers, honing their knowledge of their subject or the practice of teaching.

Two top-performing education systems in the world are Finland and Singapore offer insight on the importance of teachers. They are markedly different: in Finland, kids start school later, around 7, they don’t have too much homework, there is little high-stakes testing. In Singapore, expectations are high, kids are tested frequently, and pressure is intense.

Both systems have one thing in common: Teaching institutions are highly selective, teachers are highly-trained, and they are trusted. They are given time to work with other teachers and administrators to solve problems, in the classroom, with the curriculum, and with parents.

A big lesson: start early, invest much

Research shows that high-quality early-childhood programs can deliver an annual return of 13% per child (on the upfront costs of the program), through better outcomes in education, health, employment and social and emotional well-being. Early-childhood education, done well, helps children and parents.

The US is a global laggard in investing in early childhood programs. Even though more parents are working, enrollment in early schooling (before kindergarten) at the age of 3 in the US is 30 percentage points below the OECD average. The gap is just as stark for 4-year-olds: 87% are enrolled in pre-primary and primary education, on average, across OECD countries. In the US that figure is 66%.

In the UK, 100% of 3-year-olds were enrolled into pre-primary programs in 2015, way above the OECD average of 73%. That’s because in 2004 the British government did a report to study the effects of early-childhood education and decided the evidence was so compelling that it would provide 15 hours a week of free child-care or preschool for 38 weeks a year, or 570 hours total, for all. The benefit appears to endure: In the UK, enrollment rates for 4-6 year-olds are nearly universal and far exceed OECD averages.

The US education system is not at all equal

The US is a deeply unequal place educationally. Education should serve to mitigate socioeconomic disparities, but in the US it can exacerbate them.

“Children from similar social backgrounds can show very different performance levels, depending on the school they go to or the country they live in,” Schleicher wrote in the BBC. “And yet, results from Pisa tests [a critical-thinking test given to 15-year olds around the world] show that the 10% most disadvantaged 15-year-olds in Shanghai have better maths skills than the 10% most privileged students in the United States and several European countries.”

While a large share of Americans have a college education, the distribution of that education is huge, ranging from a low of 29% in West Virginia to a high of 63% in the District of Columbia. Among the 14 countries with regional or subnational data for this age group, only four had an equal or larger gap: Brazil, Greece, the Russian Federation and Turkey.

And social mobility is low. In the US, your chance of going to college is much higher if your parents went to college: 40% of 30-44 year-olds have at least one college-educated parent. The average among OECD countries and economies with available data is 25%. If your parent did not go to college, that figure is dramatically lower: only 19% of those without a parent who has pursued college will follow that path.

The US has not fallen from its perch completely. Foreign students still flock to the US: For each national student enrolled abroad, the US receives 21 international or foreign students.

But if it wants to hold its place, or even—imagine it—improve it, it needs to rethink its investment in teachers, and early- childhood education.