Written Replies to Parliamentary Questions

Written Reply to Parliamentary Question on Studies on the Deterrent Effect of a Life Sentence Relative to the Death Penalty, by Mr K Shanmugam, Minister for Home Affairs and Minister for Law

Published: 05 October 2020



Assoc Prof Jamus Jerome Lim: To ask the Minister for Home Affairs (a) whether there has been any systematic study by the Ministry as to the deterrent effect of a life sentence relative to the death penalty; and (b) whether the study has been conducted in cases where the reasoning capacity of the perpetrator may have been compromised such as by mental illness or addiction.  




    1. In deciding whether to apply the death penalty to a particular offence, the Government takes into account (amongst other factors) three key considerations. First, the seriousness of the offence, in terms of the harm that the offence will cause to the victim and to society. Second, how frequent or widespread the offence is. Third, the need for deterrence. These considerations are considered in totality. For example, the fact that an offence is not widespread now, may not, by itself, be a decisive factor.


    2. The death penalty is imposed for offences such as intentional murder, gang robbery with murder, trafficking of significant quantities of drugs, terrorist bombing, and the use of firearms. While the capital sentence thresholds for drug trafficking may not seem high to the layperson, they actually involve significant quantities of drugs. For example, the capital sentence threshold amount of 15g of pure heroin (diamorphine) is equivalent to 1,250 straws of heroin, and feeds 180 drug abusers for a week. This is bringing death, or at least a life of ruin, to a large number of abusers and their families.


    3. There have been some studies commissioned by the Government on the deterrent effect of the death penalty compared to life imprisonment, as well as on public views on the death penalty.


    4. Last year, the Ministry of Home Affairs (MHA) had commissioned a survey of 2,000 residents’ attitudes towards the imposition of capital punishment. The majority of the respondents agreed or strongly agreed that the death penalty is more effective than life imprisonment as a deterrent against using firearms in Singapore (70.8%), committing murder (70.6%) and drug trafficking (68%).


    5. MHA had also commissioned a study of a sample of non-Singaporeans who are likely to visit Singapore and hence might potentially encounter Singapore laws and penalties. The study was conducted in 2018. The majority (76%) believed that compared to life imprisonment, the death penalty is more effective in discouraging people from committing serious crimes (e.g. intentional murder, smuggling firearms, and drug trafficking) in Singapore. The majority (84%) also believed that compared to life imprisonment, the death penalty is more effective in discouraging people from trafficking drugs into Singapore.


    6. We want to emphasise that the studies need to be taken in context. Some tentative conclusions can be drawn, but the very nature of these studies is such that more work will have to be done over periods of time.


    7. There is also some evidence that drug traffickers who had been arrested, had known about the death penalty and the amounts that would attract the death penalty, and this had caused a reduction of the amount of drugs trafficked. MHA found that there was a 66% reduction in the average net weight trafficked for opium, in the four-year window after the mandatory death penalty was introduced in 1990 for trafficking more than 1,200g of opium. Similarly, in the four-year period after the introduction of the mandatory death penalty for trafficking involving more than 500g of cannabis in 1990, there was a 15 to 19 percentage point reduction in the probability that traffickers would choose to traffic above the capital sentence threshold.


    8. Another study conducted by MHA on convicted drug traffickers and non-drug traffickers (e.g. drug abusers) showed that traffickers who stated that they had higher awareness of and were mindful of the severe legal consequences, had limited their trafficking behavior. This points to restrictive deterrence, as trafficking activities were intentionally limited when there was greater awareness of sanctions. The majority of the offenders who were non-traffickers (85.1%) likewise felt that the death penalty has a deterrent effect.


    9. There is also some evidence of the deterrent effect of the death penalty, by reference to other offences, beyond drug trafficking.


    10. Prior to 1973, firearms robbery was on the rise, reaching a peak of 174 cases in 1973. A dramatic drop was witnessed over the decades following the introduction of the death penalty for such offences. Firearms offences immediately fell by 39% to 106 cases the next year, and fell further within the next three to four years to an even lower level, and remains at a very low level today. At Annex 1 is a chart showing this. Today, firearms robbery is rare in Singapore, with no cases reported in the last 13 years. This is an indicator of the strong deterrent effect of the death penalty.


    11. The introduction of the death penalty for kidnapping under the Punishment of Kidnapping Ordinance in 1961 likewise resulted in a dramatic drop in such cases. In the three years before 1961, there were on average, 29 kidnapping cases a year in Singapore. But this fell to only one case in 1961. Except for six cases in 1964 and three cases in 2003, kidnapping cases have not exceeded two cases per year since the death penalty was introduced. At Annex 2 is a chart showing this.


    12. There is majority public support for the death penalty. Various surveys have been conducted which show this.


    13. The Member asked about whether there has been a study of the deterrent effect of the death penalty, in respect of persons whose reasoning capacity may have been compromised by mental illness. If the offender was of unsound mind at the time of the commission of the offence, the offender will be acquitted of the offence by reason of the defence of unsoundness of mind under section 84 of the Penal Code. This defence applies to all offences, including offences outside the Penal Code.


    14. The Member asked about cases involving offenders with addiction. Intoxication – whether induced by drugs or other substances – is a defence under section 85 of the Penal Code. However, the offender needs to show that as a result of the intoxication, he did not know what he was doing, or he did not know that his conduct was wrong, and the intoxication was caused without his knowledge or against his will.


    15. The Government has the responsibility to ensure the safety and security of Singaporeans, while maintaining a fair and just criminal justice system. The rights of offenders need to be considered, in the context of the rights of victims and the right of Singaporeans to live in safety and security.


    16. The approach we have taken has resulted in Singapore being one of the safest places in the world to live. This is something deeply valued by Singaporeans.


    17. We invite the Member to share with MHA whether he is supportive of the death penalty, for what offences and why. And if he is against the death penalty, then it will also be useful to hear from him on his reasons for his position. The Member’s views will be given careful and respectful consideration.

Annex 1 (118kb, .pdf)
Annex 2 (117kb, .pdf)


Law and order