This is a great short article by Dr. Eyal Pascovich, published in Intelligence and National Security Vol. 33, that not only introduces the concept and need for the Devil's Advocate, but also provides clear cases from the Intelligence community in Israel, where this is used and the results.
Many intelligence services around the world maintain mechanisms intended to help minimize the risk of erroneous intelligence assessments. One of the best-known mechanisms is the ‘devil’s advocate’ whose goal is to present – sometimes artificially – an intelligence assessment that contradicts the prevailing view. The goal of this practice is to try to encourage doubts, both among intelligence assessors and among decision-makers. This paper will describe the importance and function of the 'devil’s advocate' mechanism in intelligence. Using Israel as a test case, the paper will seek to draw conclusions regarding the desirable format of operations of this mechanism.
Highly recommended to read this. You can download the PDF from Dr. Pascovich's Haifa University page.
Thank you PM for pointing this out to us.