Inclusion Probabilities and Dropout

Abstract: Recent discussions on a forensic discussion group highlighted the prevalence of a practice in the application of inclusion probabilities when dropout is possible that is of significant concern. In such cases, there appears to be an unpublished practice of calculation of an inclusion probability only for those loci at which the profile of interest (hereafter the suspect) is fully included among the alleles present in the crime scene sample and to omit those loci at which the suspect has alleles that are not fully represented among the alleles in the mixture. The danger is that this approach may produce apparently strong evidence against a surprisingly large fraction of noncontributors. In this paper, the risk associated with the approach of ignoring loci with discordant alleles is assessed by simulation.     

论证明标准

证明标准是证据制度的核心和灵魂。证明标准不能构筑在盖然性的基础之上,西方国家的盖然性优势标准和排除一切合理怀疑的标准(也称高度盖然率标准)均不能成立。证明标准是真实的样板。然而,历代证据制度下树立的真实样板,包括神示真实、法律真实、心证真实,均不能构成证明标准。学者们推崇的客观真实,也不能构成证明标准。司法证明的高标准是实质真实,低标准是形式真实。推定是司法证明的一种补救方法,它本身不是证明标准。     

An epistemic break from “expertise”: Misunderstanding Terrorism by Marc Sageman

ABSTRACT

Professor Marc Sageman’s latest contribution to terrorism “studies” builds on an ever-increasing critique of a field in which “expertise” is something that is largely taken for granted, rather than empirically “known”. His book Misunderstanding Terrorism seeks to refocus our attention towards what is knowable through a Bayesian analysis based on his unique access to acts of terrorism within the Western world. Key, however, is his framing of what terrorism “is”, and to that effect, this review article first assesses the work of two individuals writing on terrorism, Rafaello Pantucci and Shiraz Maher, to place Sageman’s significant book within a wider context of terrorism literature.     

Texas Population Substructure and Its Impact on Estimating the Rarity of Y STR Haplotypes from DNA Evidence*

Abstract: Three sampled populations of unrelated males—African American, Caucasian, and Hispanic, all from Texas—were typed for 16 Y short tandem repeat (STR) markers using the AmpFlSTR^® Yfiler^TM kit. These samples also were typed previously for the 13 core CODIS autosomal STR loci. Most of the 16 marker haplotypes (2478 out of 2551 distinct haplotypes) were observed only once in the data sets. Haplotype diversities were 99.88%, 99.89%, and 99.87% for the African American, Caucasian, and Hispanic sample populations, respectively. F_ST values were very small when a haplotype comprised 10–16 markers. This suggests that inclusion of substructure correction is not required. However, haplotypes consisting of fewer loci may require the inclusion of F_ST corrections. The testing of independence of autosomal and Y STRs supports the proposition that the frequencies of autosomal and Y STR profiles can be combined using the product rule.     

期待可能性理论的梳理

有必要站在非决定论的立场讨论期待可能性;有关期待可能性的部分观点分歧,缘于在不同意义上使用期待可能性概念;期待可能性虽然在德国受到冷落,但这仅限于故意的作为犯的情形,而且有其特定原因;我国目前应当采取规范责任论,使期待可能性理论发挥应有的作用;缺乏期待可能性既是某些法定的责任阻却事由的根据,也是超法规的责任阻却事由。     

Development of a Protein‐based Human Identification Capability from a Single Hair

Shed human hair (lacking root nuclear DNA) frequently contributes important information to forensic investigations involving human identification. Detection of genetic variation observed in amino acid sequences of hair proteins provides a new suite of identity markers that augment microscopic hair analysis and mitochondrial DNA sequencing. In this study, a new method that completely dissolves single hairs using a combination of heat, ultrasonication, and surfactants was developed. Dissolved proteins were digested and genetically variant peptide (GVP) profiles were obtained for single hairs (25 mm) via high‐resolution nanoflow liquid chromatography‐based mass spectrometry and a novel exome‐driven bioinformatic approach. Overall, 6519 unique peptides were identified and a total of 57 GVPs were confirmed. Random match probabilities ranged between 2.6 × 10^?2 and 6.0 × 10^?9. The new bioinformatic strategy and ability to analyze GVPs in forensically relevant samples sizes demonstrate applicability of this approach to distinguish individuals in forensic contexts.     

The use of error rates to predict and characterize the efficacy of presumptive field tests

From a forensic perspective, a presumptive test, one which indicates the presence or absence of a certain target material such as blood, is an invaluable tool. Among these tests, there are different specificities, sensitivities, and shelf lives. The accuracy of a test is an algebraic combination of the specificity and sensitivity of the test. Each test has limitations as given by its false positive and false negative rates. The aim of this study was to illustrate how the false positive and false negative rates are to be properly determined using a simulation study for the phenolphthalein test. New presumptive tests must be properly evaluated/validated through testing of commonly encountered household items and other potentially probative items usually found at crime scenes, however, the makeup of test sets must appropriately capture all error rates. In order to correctly use these results when the test is applied to an unknown sample recovered at a crime scene, the error rates cannot be applied directly to estimate whether or not the sample is actually the analyte of interest. In a validation study, the forensic scientist calculates the false positive rate as the p(Positive Reaction|Blood), whereas at the scene, the crime scene investigator wishes to determine the p(Blood|Positive Reaction). All crime scene investigators need to ensure that the conditional is not transposed when interpreting such results. Furthermore, this work provides a model for the assessment of a multiple test diagnostic system intended for investigators.     

概率理论在分析证据证明力方面的运用

由于法官的自由心证存在缺陷以及案件中证据和事实的不确定性和人类认识能力的局限性,将概率论引入司法证明领域是必要的和可行的。相对于完全依靠法官的良心和理性对证据的证明力进行认定,运用概率的方法分析证据证明力的大小就显得更为客观、准确。     

When can a DNA profile be regarded as unique?

The probability that a defendant's DNA profile is unique in a population of untyped individuals is shown to be bounded below by one minus twice the sum of the match probabilities over the population. This bound assumes that the possibility of laboratory or handling error can be neglected, and applies only when there is no non-DNA evidence in favour of the defendant. There cannot be a completely general lower bound: if there is overwhelming non-DNA evidence that the defendant is not the source of the crime stain, then that is also overwhelming evidence of non-uniqueness. Application to k-locus short tandem repeat (STR) profiles is discussed, and illustrated with calculations based on the 6-STR-locus system used in current UK casework. However, because of the problem of the non-DNA evidence, there seems to be no satisfactory way for an expert witness to address the question of uniqueness in court.     

比例责任在侵权法上的适用之检讨

传统的"全有全无原则"在处理新型侵权案件之时,难以平衡加害人和受害人的利益,比例责任作为"全有全无原则"的补充则能较好地平衡加害人和受害人的利益。比较法上,主要是在责任成立阶段,通过引入概率因果关系理论,结合损害的酌定,建构比例责任理论。我国侵权法上,比例责任还适用于责任范围的确定上,如多数人侵权"共同因果关系"案型,但是该层面的比例责任不宜扩展至单独侵权。两种类型的比例责任具有不同的教义学基础:前者的基础是《侵权责任法》的公平责任原则,其能在特殊案型中对因果关系和损害重新解释;后者的基础则是《侵权责任法》第12条。应当认识到比例责任有其适用范围和限度,其只能作为传统侵权的补充。产品侵权、医疗侵权、环境侵权和"共同因果关系"数人侵权是我国侵权法上典型的比例责任适用的案型,相关理论仍然需要进一步厘定。