What is verbal autopsy?
Critical information on population health is needed to inform planning, resource allocation, program implementation, monitoring, and evaluation. Since many countries lack complete vital registration systems, one of the key pieces of information about population health is missing – causes of death. Understanding what the most prevalent causes of death are in a given population can help target preventive interventions and provide health services.
Verbal autopsy (VA) is a method of determining individuals’ causes of death and cause-specific mortality fractions in populations without a complete vital registration system. Verbal autopsies consist of a trained interviewer using a questionnaire to collect information about the signs, symptoms, and demographic characteristics of a recently deceased person from an individual familiar with the deceased. A standard VA instrument paired with easy-to-implement and effective analytic methods can help bridge significant gaps in information about causes of death, particularly in resource-poor settings.
SmartVA-Analyze is an application that implements the Tariff 2.0 Method1 for computer certification of verbal autopsies. It takes verbal autopsy interview data as input and produces cause of death estimates at the individual and population levels. The SmartVA cause of death assignment system was designed and validated with the Population Health Metrics Research Consortium (PHMRC) Gold Standard VA database collected as part of the PHMRC Gold Standard VA Validation Study.2
The PHMRC Shortened Questionnaire is a standardized VA questionnaire developed by the Population Health Metrics Research Consortium, based on World Health Organization (WHO) standards.3 The SmartVA system is designed for analyzing VA data collected electronically using the PHMRC Full and Shortened Questionnaires with the Open Data Kit (ODK) Collect system on Android devices. Paper-based versions of the PHMRC Full and Shortened Questionnaires are also available.
PHMRC Shortened Questionnaire
PHMRC Full Questionnaire
The Population Health Metrics Research Consortium (PHMRC) Gold Standard VA Validation database is in the public domain. Download it from the Global Health Data Exchange.
The SmartVA-Analyze Application source code can be found on GitHub.
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The verbal autopsy research team’s activities provide data and resources that will be the basis for rapid and effective field assessment of population-level causes of death.
Health Metrics Science lecture series
Drs. Abraham Flaxman and Bernardo Hernández Prado present on using verbal autopsy tools to automate the cause of death certification process.
Develop high-performing methods to analyze verbal autopsy data
IHME was the lead institution in the Population Health Metrics Research Consortium (PHMRC) project, which aimed to develop methods and instruments to quantitatively assess population health. IHME collaborated with the Harvard School of Public Health, Johns Hopkins Bloomberg School of Public Health, the University of Queensland, the Research Institute for Tropical Medicine (the Philippines), the George Institute (India), King George Medical College (India), the Pemba Public Health Laboratory (Tanzania), and the Muhimbili University of Health and Allied Sciences (Tanzania) to collect over 12,500 gold standard verbal autopsies in multiple cultural and linguistic settings.
In order to validate verbal autopsy analysis methods, data were collected in hospital and clinical environments for decedents with known causes of death. The Consortium developed a list of stringent gold standard definitions for each cause of death, detailing the diagnostic criteria required to qualify for the study. Cases that met the criteria were followed with blinded VA interviews with a relative of the deceased. The VA questionnaire was used to collect information about the symptoms of the deceased, demographic characteristics, possible risk factors (such as tobacco use), and other potentially contributing characteristics.
The most commonly used approach to analyzing VA data is physician review. However, this approach can prove both time-consuming and costly. All of the gold standard cases collected as part of the PHMRC have been physician-reviewed to provide a comparison to the current standard procedures in the field. In parallel with collecting the results of the physician coding, we have been testing a suite of different methods. Three of them were previously in existence: InterVA (a program that incorporates commonly applied physician decision points by coding them into algorithms), the King-Lu method (previously developed by the PHMRC), and the Symptom Pattern Method (also previously developed by the PHMRC). In addition, we have developed a number of other methods that utilize either a tariff or a machine learning approach.
The tariff and machine learning methods outperform physician review and offer an analysis solution that is more cost-effective and less time-consuming than physician review, which could in turn result in more timely and accessible cause of death data in resource-poor settings.
Analyze community verbal autopsy data
Multiple projects, including the PHMRC and the Improving Methods to Measure Comparable Mortality by Cause project, have collected community verbal autopsies in Bangladesh, India, Mexico, Papua New Guinea, the Philippines, Sri Lanka, and Tanzania. The research team has applied multiple existing and recently developed methods to these datasets to produce population-level cause of death estimates for these sites.