对“命案必破”的思考

命案侦破是当前公安机关的一项重要任务,但目前对此仍存在一些片面认识。应正确认识命案侦破的重要意义,坚定“命案必破”的信心,进一步推进侦查破案工作,确保命案侦破工作取得有效成果。     

Novices cannot fill the examiners’ shoes: Evidence of footwear examiners’ expertise in shoe comparisons

The value of a footwear examiner’s opinion centres on their ability to determine whether a particular shoe made an impression with greater accuracy than a novice. However, there has been limited research on the expertise of footwear examiners and the accuracy and reproducibility of their decisions. In the current study, we measured the accuracy and consensus of 31 footwear examiners versus a comparison group of 29 novices. Participants completed 20 ground truth known mock shoe comparisons. Results demonstrated that footwear examiners were more accurate than novices, regardless of comparison difficulty. Overall, on trials where probative decisions were given, examiners made false identifications and false exclusions on a total of 3% and 2% of trials, while novices made false identifications and false exclusions on a total of 19% and 17% of trials. Examiners also demonstrated better consensus in their opinions than novices, although both groups demonstrated low levels of agreement in their responses and variability in their interpretation of the conclusion scale. In summary, these findings support the proposition that footwear examiners show expert-level performance in matching known and unknown footwear impressions. These performance estimates may help the criminal justice system to appropriately value footwear examination evidence.     

教育收益率的性别差异分析

很多研究均发现女性的教育收益率显著高于男性。本文利用中国城镇居民入户调查数据,也发现2004年中国城镇女性职工的教育收益率比男性高约2个百分点。进一步的分析表明,职工的教育水平与其面临的工资性别歧视程度呈反向关系,即低教育水平职工中的工资性别歧视程度更高,结果导致不同教育水平的女性之间的工资差异比男性更大,从而女性的教育收益率更高。     

Comprehensive analysis and investigation of accident/occupational disease responsibility rates: A case study for accidental CO poisoning

One of the major problems of courts and insurance companies is the lack of a proper technique to determine the rate of responsibility of the parties involved in the accident. The aim of this study was to determine the Accident/Occupational Diseases Responsibility Rates (AOD RR) for complex events. Accordingly, a case study of a complex accident of carbon monoxide (CO) poisoning was selected and Occupational Accident Tree Analysis (OATA) and Occupational Accident Component Analysis (OACA) techniques, which were solely used to investigate occupational accidents, were used with the new names Accident/Occupational Disease Tree Analysis (AOD TA) and Accident/Occupational Disease Component Analysis (AOD CA) to evaluate their applicability to investigate non-occupational accidents and occupational diseases. For this purpose, causes of CO penetration to victims’ room was assessed using gas tracking methods. Finally, Fuzzy Accident/Occupational Disease Tree/Component Analysis (FAOD TA and FAOD CA) techniques were developed and used for determining AOD RR in fuzzy environment. The results showed that the AOD RR obtained by AOD TA and AOD CA based on the average of experts’ personal opinions and consensus between experts, and AOD TA and AOD CA in a fuzzy environment were close to each other, with the power terminal and the power cable crossing route being the main routes of transmission and penetration of CO to the victims’ room. Also, the owner, contractor, tenant, and serviceman were responsible for the CO poisoning of victims. It can be concluded that any hole, crack, or fission in the building can result in CO penetration to the individuals’ living rooms, and gas tracking in early winter, especially in older buildings, plays a very significant role in preventing residents’ poisoning. Further, due to the uncertainty of AOD TA and AOD CA techniques, it is recommended to use FAOD TA and FAOD CA techniques for increasing the accuracy of the results. This will enhance the court and insurance companies’ trust in the opinions of accident investigation experts, decrease delays in the proceedings, and prevent any violation of the individual rights.     

Knowledge on DNA Success Rates to Optimize the DNA Analysis Process: From Crime Scene to Laboratory

DNA analysis has become an essential intelligence tool in the criminal justice system for the identification of possible offenders. However, it appears that about half of the processed DNA samples contains too little DNA for analysis. This study looks at DNA success rates within 28 different categories of trace exhibits and relates the DNA concentration to the characteristics of the DNA profile. Data from 2260 analyzed crime samples show that cigarettes, bloodstains, and headwear have relatively high success rates. Cartridge cases, crowbars, and tie‐wraps are on the other end of the spectrum. These objective data can assist forensics in their selection process.The DNA success probability shows a positive relation with the DNA concentration. This finding enables the laboratory to set an evidence‐based threshold value in the DNA analysis process. For instance, 958 DNA extracts had a concentration value of 6 pg/μL or less. Only 46 of the 958 low‐level extracts provided meaningful DNA profiling data.     

A Comparison of Methods for Analyzing Criminological Panel Data

We demonstrate that fixed- and random-effects models for pooled cross-sectional and time series data, and latent growth curve models for panel data are special cases of a more general model. We compare the estimates obtained from each type of model for a data set consisting of homicide rates and a vector of explanatory variables for 400 US counties over a 15-year period. Most, but not all, estimates are similar in the two models. We identify circumstances under which one approach may be advantageous to the other.

Crime is the Problem: Homicide,Acquisitive Crime,and Economic Conditions

A question that emerges from recent research on the relationship between economic conditions and street crimes committed for monetary gain concerns the effect of changing economic conditions on violent crime. I propose that the economy stimulates violent crime indirectly through its effect on acquisitive crime. This hypothesis is evaluated in fixed-effects panel models of change in acquisitive crime and homicide rates between 1970 and 2006. The analysis indicates that collective perceptions of economic conditions have a significant effect on an index of acquisitive crime and an indirect effect, through acquisitive crime, on homicide. Consistent with this result, the effect of collective economic perceptions is stronger for felony than argument-related homicides. A promising focus for future research is the role of underground markets in the production of both property and violent crime.

The private value of patents by patent characteristics: evidence from Finland

I use renewal rates and fees to estimate the private value of Finnish patents by patent characteristic. I disaggregate the value estimations by applicant, patent breadth, and technology. Firm patents are 1.5 times more valuable than patents owned by individuals. This holds also when controlling for technology and breadth. There are large differences in values between technologies but in contrast to the usual assumption made in the theoretical literature, broader patents are not necessarily more valuable than narrower ones. Patent value is skewed and therefore the number of patents should be weighted by an index when measuring technological change. I construct this index for Finnish patents and find that renewing a patent one more year signals a 1.5 times more valuable patent.      

A study of amnesia in homicide cases and forensic psychiatric experts' examination of such claims

About one third of defendants in homicide cases claim amnesia during the time of their alleged act. Examining the authenticity of claimed amnesia is a special challenge for forensic experts. Because the experts' conclusions have legal implications, it is useful to study the characteristics of defendants who claim amnesia regarding a homicidal act and how forensic experts assess these defendants' claims. The forensic psychiatric reports from 2001 to 2007 on 102 Norwegian defendants charged with homicide were assessed quantitatively with a structured rating form. Due to multiple comparisons p of .003 was chosen. Twenty-six defendants claimed partial and 17 claimed total amnesia. No significant differences in the characteristics of the defendants were found between the partial, total, and no amnesia claiming groups. Claims of partial or total amnesia did not change the procedures and content of the forensic experts' examination. A memory test was applied in only one case. Despite the seriousness of the crime and the difficulty of assessing amnesia, the experts did not apply psychological testing of memory function or appropriate tests of possible malingering. Guidelines or standardized procedures for evaluation of defendants who claim amnesia should be developed. This could eventually contribute to more reliable and valid evaluations by forensic experts and increase the probability of just court outcomes.     

论命案现场法医会诊制度

命案现场的复杂性和特殊性,要求法医工作者不断提高检验水平。法医会诊是很好的形式。建立规范、完善的法医会诊制度将促进命案的及时侦破,提高命案侦破率,维护社会治安稳定。