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Stull KE, Chu EY, Corron LK, Price MH. Mixed cumulative probit: a multivariate generalization of transition analysis that accommodates variation in the shape, spread and structure of data. ROYAL SOCIETY OPEN SCIENCE 2023; 10:220963. [PMID: 36866077 PMCID: PMC9974299 DOI: 10.1098/rsos.220963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 02/06/2023] [Indexed: 06/18/2023]
Abstract
Biological data are frequently nonlinear, heteroscedastic and conditionally dependent, and often researchers deal with missing data. To account for characteristics common in biological data in one algorithm, we developed the mixed cumulative probit (MCP), a novel latent trait model that is a formal generalization of the cumulative probit model usually used in transition analysis. Specifically, the MCP accommodates heteroscedasticity, mixtures of ordinal and continuous variables, missing values, conditional dependence and alternative specifications of the mean response and noise response. Cross-validation selects the best model parameters (mean response and the noise response for simple models, as well as conditional dependence for multivariate models), and the Kullback-Leibler divergence evaluates information gain during posterior inference to quantify mis-specified models (conditionally dependent versus conditionally independent). Two continuous and four ordinal skeletal and dental variables collected from 1296 individuals (aged birth to 22 years) from the Subadult Virtual Anthropology Database are used to introduce and demonstrate the algorithm. In addition to describing the features of the MCP, we provide material to help fit novel datasets using the MCP. The flexible, general formulation with model selection provides a process to robustly identify the modelling assumptions that are best suited for the data at hand.
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Affiliation(s)
- Kyra E. Stull
- Department of Anthropology, University of Nevada, 1664 North Virginia Street, Stop 0096, Reno, NV 89557, USA
- Forensic Anthropology Research Centre, Department of Anatomy, University of Pretoria, Private Bag x323, 0007 Pretoria, South Africa
| | - Elaine Y. Chu
- Department of Anthropology, University of Nevada, 1664 North Virginia Street, Stop 0096, Reno, NV 89557, USA
| | - Louise K. Corron
- Department of Anthropology, University of Nevada, 1664 North Virginia Street, Stop 0096, Reno, NV 89557, USA
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Heldring N, Larsson A, Rezaie AR, Råsten-Almqvist P, Zilg B. A probability model for assessing age relative to the 18-year old threshold based on magnetic resonance imaging of the knee combined with radiography of third molars in the lower jaw. Forensic Sci Int 2021; 330:111108. [PMID: 34826761 DOI: 10.1016/j.forsciint.2021.111108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 11/11/2021] [Accepted: 11/15/2021] [Indexed: 11/16/2022]
Abstract
OBJECTIVE This study aims to generate a statistical model based on magnetic resonance imaging of the knee and radiography of third molars in the lower jaw, for assessing age relative to the 18-year old threshold. METHODS In total, 58 studies correlating knee or tooth development to age were assessed, 5 studies for knee and 7 studies for tooth were included in the statistical model. The relation between the development of the anatomical site, based on a binary system, and age were estimated using logistic regression. Separate meta-populations for knee and tooth were generated from the individual based data for men and women. A weighted estimate of probabilities was made by combining the probability densities for knee and tooth. Margin of errors for males and females in different age groups and knee and tooth maturity were calculated within the larger framework of transition analysis using a logit model as a base. Evidentiary values for combinations of knee and tooth maturity were evaluated with likelihood ratios. RESULTS For males, the sensitivity for the method was calculated to 0.78 (probability of correctly classifying adults), the specificity 0.90 (probability of correctly classifying minors), the negative predictive value 0.80 (proportion identified minors are minors) and the positive predictive value 0.89 (proportion identified adults are adults) indicating a model better at identifying minors than adults. The point at which half the female population has reached closed knee lies before the 18-year threshold, adding the knee as an indicator lowers specificity and increases sensitivity. The sensitivity when using tooth as an indicator for females is 0.24 and specificity 0.97, signifying few minors misclassified as adults but also a low probability of identifying adults. The negative predictive value for women when using tooth as the sole indicator is 0.56 and positive predictive value 0.88. Probabilities were calculated for males and females assuming a uniform age distribution between 15 and 21years. The calculated margin of error of minors classified as adults in a population between 15 and 21 years with the model was 11% for males and 12% for females. Further, the evidentiary value as well as margin of error vary for different combinations of knee and tooth maturity. CONCLUSION The statistical model based on the combination of MRI knee and radiography of mandibular third molars is a valid method to assess age relative to the 18-year old threshold when applied on males and of limited value in females.
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Affiliation(s)
- Nina Heldring
- Department of Forensic Medicine, Swedish National Board of Forensic Medicine, Retzius väg 5, SE-171 65 Stockholm, Sweden
| | - André Larsson
- Department of Forensic Medicine, Swedish National Board of Forensic Medicine, Retzius väg 5, SE-171 65 Stockholm, Sweden
| | - Ali-Reza Rezaie
- Department of Forensic Medicine, Swedish National Board of Forensic Medicine, Retzius väg 5, SE-171 65 Stockholm, Sweden
| | - Petra Råsten-Almqvist
- Department of Forensic Medicine, Swedish National Board of Forensic Medicine, Retzius väg 5, SE-171 65 Stockholm, Sweden
| | - Brita Zilg
- Department of Forensic Medicine, Swedish National Board of Forensic Medicine, Retzius väg 5, SE-171 65 Stockholm, Sweden
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Minor or adult? Introducing decision analysis in forensic age estimation. Sci Justice 2020; 61:47-60. [PMID: 33357827 DOI: 10.1016/j.scijus.2020.09.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 09/16/2020] [Accepted: 09/20/2020] [Indexed: 11/20/2022]
Abstract
Nowadays, forensic age estimation takes an important role in worldwide forensic and medico-legal institutes that are solicited by judicial or administrative authorities for providing an expert report on the age of individuals. The authorities' ultimate issue of interest is often the probability that the person is younger or older than a given age threshold, which is usually the age of majority. Such information is fundamental for deciding whether a person being judged falls under the legal category of an adult. This is a decision that may have important consequences for the individual, depending on the legal framework in which the decision is made. The aim of this paper is to introduce a normative approach for assisting the authority in the decision-making process given knowledge from available findings reported by means of probabilities. The normative approach proposed here has been acknowledged in the forensic framework, and represents a promising structure for reasoning that can support the decision-making process in forensic age estimation. The paper introduces the fundamental elements of decision theory applied to the specific case of age estimation, and provides some examples to illustrate its practical application.
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Andersson MG, Ceciliason AS, Sandler H, Mostad P. Application of the Bayesian framework for forensic interpretation to casework involving postmortem interval estimates of decomposed human remains. Forensic Sci Int 2019; 301:402-414. [PMID: 31234111 DOI: 10.1016/j.forsciint.2019.05.050] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 04/24/2019] [Accepted: 05/22/2019] [Indexed: 11/27/2022]
Abstract
We demonstrate how the Bayesian framework for forensic interpretation can be adapted for casework involving postmortem intervals (PMI) utilizing taphonomic data as well as how to overcome some of the limitations of current approaches for estimating and communicating uncertainty. A model is implemented for indoor cases based on partial body scores from three different anatomical regions as correlated functions of accumulated temperature (AT). The multivariate model enables estimation of PMI for human remains also when one or two local body scores are missing or undetermined, e.g. as a result of burns, scars or covered body parts. The model was trained using the expectation maximization algorithm, enabling us to account for uncertainty of PMI and/or ambient temperature in the training data. Alternative approaches reporting the results are presented, including the likelihood curve, likelihood ratios for competing hypotheses and posterior probability distributions and credibility intervals for PMI. The applicability or the approaches in different forensic scenarios is discussed.
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Affiliation(s)
- M Gunnar Andersson
- Department of Chemistry, Environment and Feed Hygiene, The National Veterinary Institute, SE-75189 Uppsala, Sweden.
| | - Ann-Sofie Ceciliason
- Department of Surgical Sciences, Uppsala University, University hospital, SE-751 85 Uppsala, Sweden; Department of Forensic Medicine, The National board of Forensic Medicine, Box 1024, SE-751 40 Uppsala, Sweden
| | - Håkan Sandler
- Department of Surgical Sciences, Uppsala University, University hospital, SE-751 85 Uppsala, Sweden; Department of Forensic Medicine, The National board of Forensic Medicine, Box 1024, SE-751 40 Uppsala, Sweden
| | - Petter Mostad
- Mathematical Sciences, Chalmers University of Technology and University of Gothenburg, Sweden
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Rolseth V, Mosdøl A, Dahlberg PS, Ding Y, Bleka Ø, Skjerven-Martinsen M, Straumann GH, Delaveris GJM, Vist GE. Age assessment by Demirjian's development stages of the third molar: a systematic review. Eur Radiol 2018; 29:2311-2321. [PMID: 30506219 DOI: 10.1007/s00330-018-5761-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 08/21/2018] [Accepted: 09/13/2018] [Indexed: 11/28/2022]
Abstract
OBJECTIVES Radiographic evaluation of the wisdom teeth (third molar) formation is a widely used age assessment method for adolescents and young adults. This systematic review examines evidence on the agreement between Demirjian's development stages of the third molar and chronological age. METHODS We searched four databases up until May 2016 for studies reporting Demirjian's stages of third molar and confirmed chronological age of healthy individuals aged 10-25 years. Heterogeneity test of the included studies was performed. RESULTS We included 21 studies from all continents except Australia, all published after 2005. The mean chronological age for Demirjian's stages varied considerably between studies. The results from most studies were affected by age mimicry bias. Only a few of the studies based their results on an unbiased age structure, which we argue as important to provide an adequate description of the method's ability to estimate age. CONCLUSION Observed study variation in the timing of Demirjian's development stages for third molars has often been interpreted as differences between populations and ethnicities. However, we consider age mimicry to be a dominant bias in these studies. Hence, the scientific evidence is insufficient to conclude whether such differences exist. KEY POINTS • There is significant heterogeneity between studies evaluating age assessment by Demirjian's third molar development. • Most of the studies were subject to the selection bias age mimicry which can be a source of heterogeneity. • Presence of age mimicry bias makes it impossible to compare and combine results. These biased studies should not be applied as reference studies for age assessment.
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Affiliation(s)
- Veslemøy Rolseth
- Department of Forensic Sciences, Oslo University Hospital, P.O. Box 4950, Nydalen, 0424, Oslo, Norway.
| | - Annhild Mosdøl
- Division for health services, Norwegian Institute of Public Health, Oslo, Norway
| | - Pål Skage Dahlberg
- Department of Forensic Sciences, Oslo University Hospital, P.O. Box 4950, Nydalen, 0424, Oslo, Norway
| | - Yunpeng Ding
- Division for health services, Norwegian Institute of Public Health, Oslo, Norway
| | - Øyvind Bleka
- Department of Forensic Sciences, Oslo University Hospital, P.O. Box 4950, Nydalen, 0424, Oslo, Norway
| | | | - Gyri Hval Straumann
- Division for health services, Norwegian Institute of Public Health, Oslo, Norway
| | | | - Gunn Elisabeth Vist
- Division for health services, Norwegian Institute of Public Health, Oslo, Norway
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Sironi E, Pinchi V, Pradella F, Focardi M, Bozza S, Taroni F. Bayesian networks of age estimation and classification based on dental evidence: A study on the third molar mineralization. J Forensic Leg Med 2018; 55:23-32. [DOI: 10.1016/j.jflm.2018.02.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Revised: 02/04/2018] [Accepted: 02/05/2018] [Indexed: 10/18/2022]
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