Christopher Jencks, one of the great social scientists of the 20th century and a longtime summer resident of Wellfleet, died on Feb. 8, 2025 at his home in Lexington. The cause was complications of Alzheimer’s. He was 88.

Known to all as Sandy, he was born in Baltimore on Oct. 22, 1936. His father, Francis, was an architect. Sandy went to private schools and did both his undergraduate and graduate work at Harvard, where he taught for much of his career.

He was a well-loved teacher as well as an influential researcher. He was awarded tenure in Harvard’s sociology department while still in his 30s without ever having gotten a Ph.D.

Key to that achievement was his 1972 book Inequality. Sandy was the lead author of a team of seven researchers and co-authors; they did a deep examination of the widely accepted belief that education was the key to reducing inequality. But the data showed that it just wasn’t so. Too many other factors were undermining equality; education offset them only marginally.

The book is a masterpiece of careful empiricism, and it ends with this gem of a conclusion: “Ingenious manipulation of marginal institutions like the schools,” Jencks wrote, will yield progress that is only glacial. “If we want to move beyond this tradition, we will have to establish political control over the economic institutions that shape our society. This is what other countries call socialism.”

The wry, understated last line was vintage Jencks. In the U.S., socialism was the ideology that dared not speak its name.

The extended Jencks family has Wellfleet connections dating back almost a century. Sandy’s aunt Elizabeth Jencks and her husband, Harold Wrenn, bought the house at 130 School St. in 1928. The Jencks family often visited, and in 1939, Sandy’s father built a house on Bound Brook Island for his brother Gardner and his wife, Ruth. Sandy’s cousin, the sculptor Penelope Jencks, still lives there.

Ruth Jencks in turn bought a rundown beach house on the dunes just north of Newcomb Hollow. Around 1969, Sandy and his soon-to-be wife, Jane Mansbridge, known as Jenny, an eminent social scientist in her own right, began spending part of the summer there, fixing it up in lieu of rent.

After a few more years, Sandy and Jenny bought their own house that wasn’t much more than a shack on a hill overlooking Wellfleet’s Long Pond. The house is as unpretentious as its owners. Their academic schedules allowed them extended summers on the Cape.

Visitors were often charmed or mystified by the presence of a 1968 Dodge Dart convertible that lived under a tarp across from the entrance to the Long Pond cottage. It was an inheritance from Sandy’s dad. Sandy kept it as a summer car and drove it until he stopped driving. The car reflected his playful side.

As his book on inequality suggests, Sandy was a man of the left. Another Wellfleet resident and close friend, Richard Rothstein, recalls sitting on the floor of Sandy’s office at the Institute for Policy Studies in Washington in 1965 with two other leaders of Students for a Democratic Society and writing a manifesto for an antiwar demonstration. In those years, Sandy was also writing for the New Republic.

Though he remained an egalitarian, as a scholar Sandy soon tempered his radicalism in favor of what has been a lifelong signature in his scholarship: pursuing empirical inquiry, letting the chips fall, and challenging conventional wisdom, as he did in Inequality.

Sandy was part of the group that founded The American Prospect, which I still co-edit. In the first issue of the Prospect in 1990, Sandy wrote the lead piece with his then-graduate student Kathryn Edin. It was called “The Real Welfare Crisis.”

Edin had been teaching and interviewing welfare recipients. Sandy asked her if she was discovering anything interesting. Only that they all cheat, Edin told him. As Edin recalls, she didn’t immediately grasp the import of what she had found, but Sandy did. He encouraged her to do what ultimately became nearly 400 interviews in four cities.

The Jencks-Edin piece drew the paradoxical inference that welfare recipients cheated because welfare did not pay them enough to live on. “Most people assume that low benefits just force recipients to live frugally,” they wrote. “But low benefits have another, more sinister effect that neither conservatives nor liberals like to acknowledge: they force most welfare recipients to lie and cheat in order to survive.”

The piece transformed thinking about welfare reform. It launched Edin’s career as a leading scholar of poverty, welfare, and motherhood, following Sandy’s example of mixing precise use of data with deep qualitative research.

Sandy’s work often upended widely accepted assumptions and was always based on careful empiricism. His last published piece, in 2021, also in the Prospect, skewered the comforting myth that the evolution of the U.S. into a “majority-minority” country would necessarily lead to a durable progressive coalition. Trump’s second election provided the exclamation point.

Sandy was uncommonly generous to his colleagues and students. He often co-authored books with his students, which helped jump-start their careers. In 2013, in celebration of the 40th anniversary of the publication of Inequality and of his life’s work, Harvard put on a symposium in his honor called “Unequalled: The Incomparable Sandy Jencks.” The participants included luminaries from all of the social sciences.

“I learned more from Sandy than anyone else in academia, and he was one of the best people I have ever known,” wrote David Ellwood, a former Kennedy School dean and a leading scholar of welfare reform. “I am certain that hundreds of others would say the same thing.”

“He mixed deep kindness with impossibly high expectations,” Kathryn Edin said. “If you strove to meet those expectations, it was magic.”

Self-effacing and almost shy, Sandy Jencks combined relentless intellectual curiosity, high principle, and personal modesty. Unlike many great men, Sandy was always more comfortable posing questions than holding forth. It was how he taught students and colleagues. It made him great company and a treasured friend.

Sandy is survived by his wife, Jenny, their son, Nathaniel, and a grandson, Wilder. There will be a memorial event in the spring.