Who Chooses Nobel Winners? William Kaelin Jr., Peter Ratcliffe and Gregg Semenza Win Nobel Prize in Medicine

The Nobel Committee and Assembly are responsible for selecting Nobel Prize winners and this year, William Kaelin Jr., Sir Peter Ratcliffe and Gregg Semenza were jointly awarded the Nobel Prize for Medicine.

Little is known about this year's selection process for the award, as the information can't be revealed until 50 years later, according to the Nobel Prize website. However, people must be invited to make a nomination, which the Nobel Committee considers before passing candidates along to the Nobel Assembly, who chooses the winner.

The committee's decision was announced on Monday at the Karolinska Institute in Stockholm, Sweden. Kaelin, Ratcliffe and Semenza were selected for their "discoveries of how cells sense and adapt to oxygen availability."

Oxygen availability, according to the Nobel Prize, is "central" to many diseases and the laureates discoveries were of "fundamental importance" for physiology. They also "paved the way" for breakthroughs in fighting anemia, cancer and other diseases.

nobel prize medicine winners committee assembly
Nobel Assembly members Patrik Ernfors, Anna Wedell and Randall Johnson sit in front of a screen displaying the winners of the 2019 Nobel Prize in Physiology or Medicine Gregg Semenza, Peter Ratcliffe and William Kaelin after their names were announced during a press conference at the Karolinska Institute in Stockholm on Monday. The Assembly is responsible for choosing a winner from candidates selected by the Nobel Committee. JONATHAN NACKSTRAND/AFP/Getty

Nominations for the Nobel Prize are kept in secrecy for 50 years and all invitations to nominate are confidential. Invitation letters are sent out in September to more than 3,000 people determined to be competent and qualified to nominate candidates, identified as:

  • Members of the Nobel Assembly at Karolinska Institute, Stockholm
  • Swedish and foreign members of the Medicine and Biology classes of the Royal Swedish Academy of Sciences
  • Nobel Laureates in Physiology or Medicine and Chemistry
  • Members of the Nobel Committee
  • Holders of established posts as full professors at the faculties of medicine in Sweden and holders of similar posts at the faculties of medicine or similar institutions in Denmark, Finland, Iceland and Norway
  • Holders of similar posts at no fewer than six other faculties of medicine at universities around the world, selected by the Nobel Assembly, with a view to ensuring the appropriate distribution of the task among various countries
  • Scientists whom the Nobel Assembly may otherwise see fit to approach

After those invited to nominate have submitted proposals, which must be done by January 31, the Nobel Committee reviews the nominations and selects candidates. The committee is made up of five members of the Nobel Assembly and the Secretary of the Nobel Committee and Noble Assembly. Then, the Nobel Assembly, which has 50 members, selects the winner or winners.

"The Nobel Prize for Physiology or Medicine is awarded for the discovery of major importance in life science or medicine," the Nobel Prize website explained. "Discoveries that have changed the scientific paradigm and are of great benefit for mankind are awarded the prize, whereas lifetime achievements or scientific leadership cannot be considered for the Nobel Prize."

To help the Committee select its candidates, international reputable experts are invited to create evaluation reports on nominations, which are submitted by the middle of August. In September, the Committee submits its recommendations; discussion among Assembly members ensues, followed by a vote. Laureates are selected through a majority vote and the decision is final.

The accomplishments of the Laureates are celebrated on December 10in Stockholm at a Nobel Prize Award Ceremony.