Erna Schneider Hoover (born June 19, 1926) is an American mathematician who invented a computerized telephone switching method which "revolutionized modern communication". It prevented system overloads by monitoring call center traffic and prioritizing tasks on phone switching systems to enable more robust service during peak calling times. At Bell Laboratories where she worked for over 32 years, Hoover was described as a pioneer for women in the field of computer technology.

Erna Schneider was born on June 19, 1926, in Irvington, New Jersey. Her family lived in South Orange, New Jersey and her father was a dentist and her mother was a teacher. She had a younger brother who died from polio at the age of five. She loved swimming, sailing, canoeing, and became interested in science at an early age. According to one source, she read the biography of Marie Curie which suggested to her that she could succeed in a scientific field despite the prevailing ideas about gender roles. She graduated from Columbia High School in nearby Maplewood in 1944, which would induct her into its hall of fame in 2007.

Hoover attended Wellesley College where she studied classical and medieval philosophy and history. She graduated from Wellesley in 1948 with honors, earning a bachelor's degree, was inducted into Phi Beta Kappa and was honored as a Durant Scholar. She earned her PhD from Yale University in philosophy and foundations of mathematics in 1951. Around that time, there were very few women who graduated with a PhD in philosophy (5%), compared to men.

While at Yale, she met Charles Wilson Hoover, Jr. She married him in 1953, during her three year stint teaching at Swarthmore (1951–1954). They had three daughters.

Hoover was a professor at Swarthmore College from 1951 to 1954 where she taught philosophy and logic. However, she had been unable to win a tenure-track position, possibly because of her gender and marital status, according to one view. Her husband was very supportive of his wife's career pursuits. When they moved to Summit, New Jersey in 1954, for his new job at Bell Laboratories, she had difficulty finding a teaching job. Instead, she joined her husband's employer as a senior technical associate, and was promoted in 1956. According to one source, the internal training program was the "equivalent of a master's degree in computer science." Switching systems were moving from electronic to computer-based technologies. Problems happened when a call center would be inundated with thousands of calls in a short amount of time, overwhelming the unreliable electronic relays, and causing the entire system to "freeze up."

Hoover used her knowledge of symbolic logic and feedback theory to program the control mechanisms of a call center to use data about incoming calls to impose order on the whole system. It used computer electronic methods to monitor the frequency of incoming calls at different times. Her method gave priority to processes that were concerned with the input and output of the switch over processes that were less important such as record keeping and billing. The computer, as a result, would adjust the call center's acceptance rate automatically, greatly reducing the overloading problem. The system became known as stored program control.

Hoover's thinking about the invention happened while she was in a hospital recuperating after having given birth to her second daughter, according to several sources. Lawyers for Bell Labs handling the patent had to go to her house to visit her while she was on maternity leave so that she could sign the papers. The result of the invention was much more robust service to callers during peak load times:

To my mind it was kind of common sense ... I designed the executive program for handling situations when there are too many calls, to keep it operating efficiently without hanging up on itself. Basically it was designed to keep the machine from throwing up its hands and going berserk.