Rummel estimated that a total of 212 million people were killed by all governments during the 20th century,[3] of which 148 million were killed by Communist governments from 1917 to 1987.[4] To give some perspective on these numbers, Rummel stated that all domestic and foreign wars during the 20th century killed in combat around 41 million. His figures for Communist governments have been criticized for the methodology which he used to arrive at them, and they have also been criticized for being higher than the figures which have been given by most scholars.[5][6][7][8][9][10][11] In his last book, Rummel increased his estimate to over 272 million innocent, non-combatant civilians who were murdered by their own governments during the 20th century.[12] Rummel stated that his 272 million death estimate was his lower, more prudent figure, stating that it "could be over 400,000,000."[13] Rummel came to the conclusion that a democracy is the form of government which is least likely to kill its citizens because democracies do not tend to wage wars against each other.[2] This latest view is a concept, which was further developed by Rummel, known as the democratic peace theory.[14]
Rummel was the author of twenty-four scholarly books, and he published his major results between 1975 and 1981 in Understanding Conflict and War (1975).[15] He spent the next fifteen years refining the underlying theory and testing it empirically on new data, against the empirical results of others, and on case studies. He summed up his research in Power Kills (1997).[16] His other works include Lethal Politics: Soviet Genocides and Mass Murders 1917–1987 (1990),[17]China's Bloody Century: Genocide and Mass Murder Since 1900 (1991),[18]Democide: Nazi Genocide and Mass Murder (1992),[19]Death by Government: Genocide and Mass Murder Since 1900 (1994),[20] and Statistics of Democide (1997).[21] Extracts, figures, and tables from the books, including his sources and details regarding the calculations, are available online on his website. Rummel also authored Applied Factor Analysis (1970)[22] and Understanding Correlation (1976).[23]
^"Rudolph Joseph Rummel". Honolulu Hawaii Obituaries. March 8, 2014. Retrieved August 31, 2021 – via Hawaii Newspaper Obituaries.
^Rummel, Rudolph (2007). The Blue Book of Freedom: Ending Famine, Poverty, Democide, and War (paperback ed.). Nashville, Tennessee: Cumberland House Publishing. p. 99. ISBN9781581826203.
^Harff, Barbara (Summer 1996). "Review. Reviewed Work: Death by Government by R. J. Rummel". The Journal of Interdisciplinary History. 27 (1). Boston, Massachusetts: The MIT Press: 117–119. doi:10.2307/206491. JSTOR206491.
^Kuromiya, Hiroaki (January 2001). "Review Article: Communism and Terror". Journal of Contemporary History. 36 (1). Thousand Oaks, California: SAGE Publications: 191–201. doi:10.1177/002200940103600110. JSTOR261138. S2CID49573923.
^Paczkowski, Andrzej (Spring 2001). "The Storm over The Black Book". The Wilson Quarterly. 25 (2). Washington, D.C.: Woodrow Wilson International Center for Scholars: 28–34. JSTOR40260182. Retrieved 31 August 2021 – via Wilson Quarterly Archives.
^Weiner, Amir (Winter 2002). "Review. Reviewed Work: The Black Book of Communism: Crimes, Terror, Repression by Stéphane Courtois, Nicolas Werth, Jean-Louis Panné, Andrzej Paczkowski, Karel Bartošek, Jean-Louis Margolin, Jonathan Murphy, Mark Kramer". The Journal of Interdisciplinary History. 32 (3). Boston, Massachusetts: The MIT Press: 450–452. doi:10.1162/002219502753364263. JSTOR3656222. S2CID142217169.
^Dulić, Tomislav (January 2004). "Tito's Slaughterhouse: A Critical Analysis of Rummel's Work on Democide". Journal of Peace Research. 41 (1). Thousand Oaks, California: SAGE Publications: 85–102. doi:10.1177/0022343304040051. JSTOR4149657. S2CID145120734.
^Karlsson, Klas-Göran; Schoenhals, Michael, eds. (2008). Crimes Against Humanity under Communist Regimes – Research Review(PDF). Stockholm, Sweden: Forum for Living History. pp. 35, 79. ISBN9789197748728. Retrieved November 17, 2021 – via Forum för levande historia. While Jerry Hough suggested Stalin's terror claimed tens of thousands of victims, R.J. Rummel puts the death toll of Soviet communist terror between 1917 and 1987 at 61,911,000. In both cases, these figures are based on an ideological preunderstanding and speculative and sweeping calculations. On the other hand, the considerably lower figures in terms of numbers of Gulag prisoners presented by Russian researchers during the glasnost period have been relatively widely accepted. ... It could, quite rightly, be claimed that the opinions that Rummel presents here (they are hardly an example of a serious and empirically-based writing of history) do not deserve to be mentioned in a research review, but they are still perhaps worth bringing up on the basis of the interest in him in the blogosphere.
^Rummel, Rudolph (2007). The Blue Book of Freedom: Ending Famine, Poverty, Democide, and War (paperback ed.). Nashville, Tennessee: Cumberland House Publishing. p. 11. ISBN9781581826203.
^Rummel, Rudolph (2007). The Blue Book of Freedom: Ending Famine, Poverty, Democide, and War (paperback ed.). Nashville, Tennessee: Cumberland House Publishing. p. 75. ISBN9781581826203.
^"About R.J. Rummel". Freedom, Democide, War. University of Hawaiʻi. Retrieved August 31, 2021 – via University of Hawaii System.
^Rummel, Rudolph (1975). Understanding Conflict and War. Beverly Hills, California: SAGE Publications. ISBN9780803915572. Retrieved August 31, 2021 – via Freedom, Democide, War at the University of Hawaii System.
^Rummel, Rudolph (1991). China's Bloody Century (1st hardback ed.). New Brunswick, New Jersey: Transaction Publishers. ISBN9780887384172. Retrieved August 31, 2021 – via Freedom, Democide, War at the University of Hawaiʻi System.
^Rummel, Rudolph (1992). Democide: Nazi Genocide and Mass Murder (1st ed.). New Brunswick, New Jersey: Transaction Publishers. ISBN9781412821476. Retrieved August 31, 2021 – via Freedom, Democide, War at the University of Hawaiʻi System.
^Rummel, Rudolph (2003) [1997]. Statistic of Democide: Genocide and Mass Murder Since 1900 (hardback ed.). Charlottesville, Virginia: Center for National Security Law, School of Law, University of Virginia; Transaction Publishers, Rutgers University. ISBN9783825840105. Retrieved August 31, 2021 – via Freedom, Democide, War at the University of Hawaiʻi System.
^Rummel, Rudolph (1988) [1970]. Applied Factor Analysis (1st ed.). Evanston, Illinois: Northwestern University Press. ISBN9780810108240. Retrieved August 31, 2021 – via Freedom, Democide, War at University of Hawaiʻi System.
^Rummel, Rudolph (1976). Understanding Correlation. Honolulu, Hawaii: Department of Political Science, University of Hawaiʻi. Retrieved August 31, 2021 – via Freedom, Democide, War at University of Hawaiʻi System.