What incredible results from such simple, low-cost interventions! It reminds me of the texts that Success Academies sends to parents to remind them to read to their children for at least 30 min a day. These little things really work!

There are enormous inequalities in education in the United States. A child born into a poor family has only a 9 percent chance of getting a college degree, but the odds are 54 percent for a child in a high-income family. These gaps open early, with poor children less prepared than their kindergarten classmates.

How can we close these gaps? Contentious, ambitious reforms of the education system crowd the headlines: the Common Core, the elimination of teacher tenure, charter schools. The debate is heated and sometimes impolite (a recent book about education is called "The Teacher Wars").

Yet as these debates rage, researchers have been quietly finding small, effective ways to improve education. They have identified behavioral "nudges" that prod students and their families to take small steps that can make big differences in learning. These measures are cheap, so schools or nonprofits could use them immediately.

Let's start with college. At every step of the way, low-income students are more likely to stumble on the path to higher education. Even the summer after high school is a perilous time, with 20 percent of those who plan to attend college not actually enrolling — a phenomenon known as "summer melt." Bureaucratic barriers, like the labyrinthine process of applying for financial aid, explain some of the drop-off.

While they were graduate students at Harvard, two young professors designed and tested a programto help students stick to their college plans. Benjamin L. Castleman, now at the University of Virginia, and Lindsay C. Page, at the University of Pittsburgh, set up a system of automatic, personalized text messages that reminded high school students about their college deadlines. The texts included links to required forms and live counselors.

The result? Students who received the texts were more likely to enroll in college: 70 percent, compared with 63 percent of those who did not get them. Seven percentage points is a big increase in this field, similar to the gains produced by scholarships that cost thousands of dollars. Yet this program cost only $7 per student.

The same researchers also tested a texting program to keep students from dropping out of college. The problem is important because the graduation rate of low-income college students is dismally low; two-thirds leave without a degree. Community college students received texts reminding them to complete their re-enrollment forms, particularly aid applications. Among freshmen who received the texts, 68 percent went on to complete their sophomore year, compared with 54 percent of those who got no nudges. This, too, is a big impact — especially for a program that cost only $5 per student.