A Question on Reddit by u/DrCharlesTinglePHD)
I'm wondering about this because I have read differing estimates of the count, and differing estimates of the various causes (starvation, murder, etc.). I have many books on Cambodian history, but what I believe to be the most trustworthy one (A History of Cambodia, 4th edition, by David Chandler) is probably out of date.
Also for context, what was the population of Cambodia before Lon Nol took over from Sihanouk? And do we have any idea what was it when Pol Pot took over from Lon Nol?
I'm also interested in the count of executions by motivation - e.g. how many were killed because they were Vietnamese, how many were killed because they were the wrong class, how many were killed for no reason at all, etc.
I would say that the most recent, well researched and accurate estimates of the death toll in Democratic Kampuchea came out of the Demographic Expertise Report titled Khmer Rouge Victims in Cambodia April 1975 - January 1979 by Tabeau and Kheam. This report was compiled as part of the proceedings of the ECCC and the Office of Co-Investigative Judges. It is an assessment of most, if not all, of the major estimates made of the death toll by various sources and includes much of the information you seek, including cause of death (indirect versus direct), estimates of population sizes and evidence which can be used to base these assessments.
I will be using this document to answer the questions you have but feel free to read it yourself as it can be downloaded here.
The report does not differ too much from the more common overall estimates that you would probably already find in the sources you own, indeed in the one you believe ‘most trustworthy’, Professor Chandler states that Life was hard everywhere. On a national scale it is estimated that over the lifetime of the regime nearly two million people – or one person in four – died as a result of DK policies and actions.
The Demographic Expertise Report places the estimate of the death toll under the Khmer Rouge to be most likely 1.747 to 2.2 million. This estimate is based on the most reliable methods, including projections of population growth based on statistics data prior to and following the regime’s time in power, as well as the death toll linked to mass grave records. This is coupled with research reports, surveys, survivor’s accounts and relevant expert opinions from NGOs and independent researchers. Estimates which posit numbers vastly below this, such as Michael Vickery’s, can come from using a much lower population size at the beginning of the regime. They can also be influenced by what the expert demographers say would be ‘some pre-determined views on what kind of outcome should be obtained’ (read as biased and agenda driven).
Population Prior to DK
The population estimates which the experts find most reliable for the period prior to the regime coming to power (April 1975) is 7.844 to 8.102 million, with the central value of 7.894 million. The population estimates of 1970 (beginning of Lon Nol Period) are from 7-7.662 million. The death toll estimate they feel is most appropriate for the civil war is 250,000, which is generally lower than what is usually given in figures which often exceed half a million.
Causes of Death
As the most likely estimate of about two million deaths is given, you would no doubt be familiar with ideas about how these excess deaths occurred. Starvation, overwork and disease were all prevalent in DK, and much of this prevalence is explained through policies of the Khmer Rouge. What the Demographic Expertise Report suggests however, is that the weighting of these ‘excess deaths’ to ‘direct deaths’ (meaning from violence/executions) may be more even than in earlier estimates. They conclude, and using mass grave data as evidence, that the violent deaths at the hands of the Khmer Rouge may account for at least 1.1 million deaths. So at least 50 percent of the death toll was the result of execution.
Unfortunately, it is harder to ascertain the answers to some of your follow up questions regarding why certain deaths may have occurred. All that you can work back from are statistics about different ethnic population sizes or in the case of policies relating to targeting ‘class enemies’ (such as the New People/April 17 People) how many from urban backgrounds can be counted before and after the regime. For instance, if there were two million urban Khmer as part of the ‘New People’ category defined under DK, and 500,000 perished, you can make assumptions about that cause of death relating to class status, but you cannot pinpoint the actual reason they died. They died at a higher rate, for various reasons.
There is a similar case in relation to ethnic minorities, and the Demographic Expertise Report notes that Kiernan’s estimates are most convincing, as are his opinions about why they may have been targeted at a higher rate. But they do recognise that there is a degree of uncertainty about the estimates as there are a lack of reliable sources on ethnic groups in Cambodia in the 1970s. Generally it is thought that the remaining Vietnamese within the country, perhaps around 20,000, were all killed during DK. Again, whether 100% of those deaths were the result of these people being targeted on the basis that they were Vietnamese, is hard to nail down.
In an interview I conducted with Professor Chandler in 2018, he claimed that Kiernan’s numbers were subject to significant estimation, based on very little. Watch that interview here
The general estimate of 1.75-2.2 million dying, either indirectly or directly, in DK that has been given in most reputable sources on the matter in the last few decades still holds true. In fact with projects like DCCAM’s Mass Grave Mapping, these estimates have become better evidenced than when they were originally made and can be used to claim even more violent deaths at the hands of the regime than previously thought. While we will never know how many died for precise reasons, the numbers of who were more likely to die and perhaps what policies influenced that treatment are substantiated. If we take the number of those dying directly at the hands of the regime, and presume these killings to be ideologically motivated, than we can say somewhere in excess of one million people were killed for these political reasons during the roughly four years of DK. The most generalised reason you could give to account for their deaths would be under the heading of ‘counter-revolutionaries’, which would take into account killings for breaking rules, for not having the right class background, for being an ethnic or religious minority or a suspected traitor to the regime.