Sigma Xi is the national research and scientific honor society. Its purpose is the encouragement of "original investigation in science, pure and applied."
The following mission statement was adopted by Sigma Xi's Board of Directors in 1989. "The missions of Sigma Xi are to honor scientific accomplishments, to encourage and to enhance the worldwide appreciation and support of original investigation in science and technology, and to foster worldwide a creative and dynamic interaction among science, technology, and society." This statement outlines the purposes and goals of the society for its second century.
Sigma Xi was founded in 1886 by a group of Cornell University students and a faculty member who believed that the time had come to establish an honor society for scientists and engineers. Although societies such as Phi Beta Kappa were well established in the humanities, no comparable institution existed for science scholars. In order to fill this void, the Cornell group established a society to reward excellence in scientific research and to encourage a sense of companionship and cooperation among scientists in all fields. They called the organization Sigma Xi. Later, a motto based on these initials was adopted to confirm the purpose of the society: "Spoudon Xynones," or "Companions in Zealous Research." The first women were elected to membership two years after Sigma Xi was founded.
Since 1886, Sigma Xi has grown to include more than 500 chapters and clubs across North America and a limited number of groups abroad. Although until World War II Sigma Xi groups had been situated almost exclusively at academic institutions, many members recognized that much scientific research was being performed at government and industrial laboratories. To serve scientists in these locations, the Scientific Research Society of America (RESA) was formed. In 1974, RESA and Sigma Xi merged, and in 1976, the society adopted its present name: Sigma Xi, The Scientific Research Society. Election to Sigma Xi is for life, and acceptance of membership carries certain obligations. The bylaws of the society require that each Member-elect and Associate Member-elect must assent, either orally or in writing, to the Pledge of the Society: "I hereby pledge myself, in accordance with the purposes and objectives of Sigma Xi, The Scientific Research Society, to foster companionship and cooperation among scientists, to maintain honor, integrity, and honesty in all scientific activities, and to assume the other continuing responsibilities of membership." One of the best ways to fulfill these obligations is through active membership in the society, including payment of annual dues, participation in chapter or club activities, and recommendation of qualified individuals for membership. Since its creation, Sigma Xi has elected more than 375,000 members; more than 100,000 members are currently active.