Schlesinger founded the company in 1967, primarily conducting quantitative studies door-to-door. The firm opened its first viewing facility in New Jersey in 1986 and eventually grew to have offices across the US and two in the UK.

Her son Steve Schlesinger, the company’s CEO, said: “Sarah’s tenure in the industry was well recognised and respected through her strong contribution to shaping the reputation of marketing research services as we know them today. She will be deeply missed by all of us.”

Daughter Debbie Schlesinger-Hellman, the firm’s executive vice president, added: “Watching the company grow into the business it has become today was one of the joys of my mother’s life. Her passion for research and relationships inspired us not only to succeed but to care about how we succeed and to build strong friendships along the way.”