Although the origin of professional codes of ethics can be traced back to ancient Greece, their peak was in the late twentieth century with more than 70% of codes of ethics being created after 1990. Today professional ethical standards are formulated as codes of ethics, sets of principles or guidelines, declarations, conventions, charters, or laws, and they differ in scope, form, and content. As there is no consensus on what is meant by "research ethics" and "research integrity," both concepts are clarified here.