Error Rates for Unvalidated Medical Age Assessment Procedures

During 2014-15 Sweden received asylum applications from more than 240.000 people, of which more than 40.000 were termed unaccompanied minors. In a large number of cases, claims by asylum seekers of being below 18 years were not trusted by Swedish authorities. To handle the situation, the Swedish national board of forensic medicine (R\"attsmedicinalverket, RMV) was assigned by the government to create a centralized system for medical age assessments. RMV introduced a procedure including two biological age indicators; x-ray of the third molars and magnetic resonance imaging of the distal femoral epiphysis. In 2017 a total of 9617 males and 337 females were subjected to this procedure. No validation study for the procedure was however published, and the observed number of cases with different maturity combinations in teeth and femur were unexpected given the claims originally made by RMV. Such unexpected results might be caused by systematic errors and need to be analysed thoroughly. In the present paper we present a general stochastic model enabling us to study which combinations of age indicator model parameters and age population profiles are consistent with the observed 2017 data for males. We find that, contrary to some RMV claims, maturity of the femur, as observed by RMV, appears on average well before maturity of teeth. Although results naturally contain much uncertainty, we find that classification error rates for certain groups who based on the RMV procedure are classified as above 18 years may be around 10-30%, possibly as high as 50%

Homicide Injury Quantification : Measures of injury severity in homicide victims and associations with homicide characteristics

Some previous studies have found that the amount and severity of injuries in homicide victims correlate with different homicide characteristics, such as the victim-offender relationship and drug influence of the offender. If such relationships exist, they may be used by homicide investigators as part of an offender profiling. Furthermore, injury severity may be helpful in understanding the nature of lethal violence. If the injuries change over time or differ between regions, this may say something about the underlying causes and thus help society to take preventive measures. However, measures of injury severity are often missing in homicide epidemiology. This may in part be due to a lack of standardized and accessible ways to quantify injuries in homicide victim. To address these issues, there is a need for methods to quantify injury severity in homicide victims. The aim of the current thesis was to investigate different types of injury measures and their applicability to homicide victims. The aim was also to use such measures to address research questions related to offender profiling. Starting off with injury scores used in trauma research and two scores developed specifically for homicide victims, these measures were applied to a general homicide population. Since there is no obvious “gold standard” for injury severity quantification on homicide victims, one had to be defined to validate the applied methods. Out of forensic experience and rational reasoning, the Sum of all AIS scores (SAIS) was proposed as a reference measure. The other scores were then evaluated through their correlations with the SAIS. In the following study, the injury severity in homicides from different time periods was measured. There were statistically significant increases over time with respect to excessive injuries and the number of lethal injuries per victim. These changes can reflect both a brutalization of homicidal violence, improved trauma care, or shifts in the methods by which people are killed. Next, the associations between injury severity and homicide characteristics were analysed. No relevant associations between injury severity and victim-offender relationship were found. Neither were there any connections between benzodiazepine influence in the offender and injury severity on the victim. Thus, the studies do not support the use of injury severity scores for offender profiling in a general homicide population

When is a postmortem examination carried out? : A retrospective analysis of all Swedish deaths 1999-2018

The objective of this study was to assess who is merited an autopsy in Sweden. Data from the Swedish cause of death (COD) registry over a period of 20 years was retrieved and analysed. A multinominal logistic regression analysis was performed to identify the variables that were most strongly associated with the performance of a clinical or forensic autopsy (CA/FA). A definite COD, i.e. a COD based on autopsy findings, was registered in 12.6% of all deceased during the investigated period. In the remaining cases, the COD was presumed by the clinicians. Being male, born in the Nordic region, dying in a private residence, and unnatural death were most strongly associated with the performance of CA/FA. In contrast, being female, dying from dementia, dying at a nursing home, being born outside of Europe, or living in a small city or rural area seldom led to the performance of CA/FA. The above is certainly surprising as an autopsy provides an opportunity to investigate the cause of death, validate clinical diagnoses, detect unexpected aberrations, audit health care, and provide feedback to clinicians to facilitate their continuing education

Quantifying Homicide Injuries : A Swedish Time Trend Study Using the Homicide Injury Scale

Studies report that the homicide rate has decreased considerably in most Western countries since the 1990s. However, few studies have examined the level of injury in homicides. The injury severity in homicide victims was studied in the Stockholm area using both the Homicide Injury Scale (HIS) and the number of lethal injuries per victim. Cases were included from four periods; 1976-78, 1986- 88, 1996-98, and 2006-08. The number of homicides with overkill according to the HIS was significantly higher in 1996-98 compared to 1976-78. Compared with 1976-78, the number of lethal injuries per victim was significantly higher both in 1986-88 and 1996-98. There are various possible reasons for the changes, including a brutalization of lethal violence or a more effective trauma care. More in-depth analysis of individual cases together with research on victims of attempted homicides is needed to explain these shifts in injury severity

Quantifying Homicide Injuries: A Swedish Time Trend Study Using the Homicide Injury Scale

Studies report that the homicide rate has decreased considerably in most Western countries since the 1990s. However, few studies have examined the level of injury in homicides. The injury severity in homicide victims was studied in the Stockholm area using both the Homicide Injury Scale (HIS) and the number of lethal injuries per victim. Cases were included from four periods; 1976-78, 1986-88, 1996-98, and 2006-08. The number of homicides with overkill according to the HIS was significantly higher in 1996-98 compared to 1976-78. Compared with 1976-78, the number of lethal injuries per victim was significantly higher both in 1996-98 and 2006-2008. There are various possible reasons for the changes, including a brutalization of lethal violence or a more effective trauma care. More in-depth analysis of individual cases together with research on victims of attempted homicides is needed to explain these shifts in injury severity

Mathematically optimal decisions in forensic age assessment

Forensic age estimation generally involves considerable amounts of uncertainty. Forensic age indicators such as teeth orskeleton images predict age only approximately, and this is likely to remain true even for future forensic age indicators.Thus, forensic age assessment should aim to make the best possible decisions under uncertainty. In this paper, we applymathematical theory to make statistically optimal decisions to age assessment. Such an application is fairly straightforwardassuming there is a standardized procedure for obtaining age indicator information from individuals, assuming we have datafrom the application of this procedure to a group of persons with known ages, and assuming the starting point for eachindividual is a probability distribution describing prior knowledge about the persons age. The main problem is then to obtainsuch a prior. Our analysis indicates that individual priors rather than a common prior for all persons may be necessary.We suggest that caseworkers, based on individual case information, may select a prior from a menu of priors. We showhow information may then be collected over time to gradually increase the robustness of the decision procedure. We alsoshow how replacing individual prior distributions for age with individual prior odds for being above an age limit cannot berecommended as a general method. Our theoretical framework is applied to data where the maturity of the distal femur andthe third molar is observed using MRI. As part of this analysis we observe a weak positive conditional correlation betweenmaturity of the two body parts