Background Cause-specific mortality statistics remain scarce for the majority of low-income countries, where the highest disease burdens are experienced. Neither facility-based information systems nor vital registration provide adequate or representative data. The expansion of sample vital registration with verbal autopsy procedures represents the most promising interim solution for this problem. The development and validation of core verbal autopsy forms and suitable coding and tabulation procedures are an essential first step to extending the benefits of this method. Methods and Findings Core forms for peri- and neonatal, child, and adult deaths were developed and revised over 12 y through a project of the Tanzanian Ministry of Health and were applied to over 50,000 deaths. The contents of the core forms draw upon and are generally comparable with previously proposed verbal autopsy procedures. The core forms and coding procedures based on the International Statistical Classification of Diseases (ICD) were further adapted for use in China. These forms, the ICD tabulation list, the summary validation protocol, and the summary validation results from Tanzania and China are presented here. Conclusions The procedures are capable of providing reasonable mortality estimates as adjudged against stated performance criteria for several common causes of death in two countries with radically different cause structures of mortality. However, the specific causes for which the procedures perform well varied between the two settings because of differences in the underlying prevalence of the main causes of death. These differences serve to emphasize the need to undertake validation studies of verbal autopsy procedures when they are applied in new epidemiological settings., A procedure for recording verbal autopsy information was tested in two countries and found to be capable of providing reasonable mortality data. The need to undertake validation studies was also demonstrated., Editors' Summary Background. People living in developed countries take it for granted that when a loved one dies an accurate cause-of-death certificate will be issued. But for two-thirds of the deaths that occur worldwide, there are no certificates. Detailed information about what people die from is unavailable for more than 50% of countries, many of which have high death rates. This information is badly needed for public-health planning, for using scarce health resources wisely, and for monitoring the effect of new health initiatives. One way to improve knowledge about what people die from is a procedure called verbal autopsy (VA). Relatives or caregivers are interviewed about the symptoms experienced by the deceased before their death and the circumstances surrounding their death by trained personnel who use a standard form. Doctors then review the completed VA forms and assign a specific cause of death from a short version of the International Classifications of Diseases, or ICD, an internationally agreed on list of codes for hundreds of diseases. Why Was This Study Done? VA procedures are being developed in many countries, but each step in a VA can be affected by factors that vary from place to place, such as how long after the death the interview is done, the training that interviewers receive, how the questions are worded, and the locally common diseases, which tend to be recognized better than rare diseases. To ensure that the data collected are accurate and comparable between countries and also over time, VA procedures need to be standardized. In this study, the researchers describe their efforts to achieve this through the development and validation of core VA procedures. What Did the Researchers Do and Find? In 2001, the researchers refined the VA forms that were being used in Tanzania for deaths occurring around the time of birth and for deaths occurring in childhood and adulthood. They then translated the forms for use in China, adapting them slightly to allow for cultural differences in how symptoms are described. They also drew up a short list of ICD codes to use in tabulating and validating important causes of death. Then, for four years, they collected VA and medical record information for the same deceased individuals and measured how well the VA procedure agreed with the medical record information in both countries. They found that the procedure could be transferred between China and Tanzania but that it performed rather differently for different causes of death in the two countries. So, in both countries, the procedure accurately recorded tuberculosis, cerebrovascular diseases such as strokes, and transport accidents as causes of death. But some other causes of death were accurately recorded in one country only—generally the common diseases in that country—and many causes of death were inaccurately reported in both countries. What Do These Findings Mean? The researchers use their experience of developing VAs for use in Tanzania and China and the results of this study to make several recommendations about how to develop standardized VA procedures that will yield accurate cause of death. For example, they suggest that the VA form should contain a detailed core symptom duration checklist and only a short space for a narrative history (an open-ended description of the last illness provided by the relative or caregiver) because long narrative histories are hard to standardize. They discuss the need to adapt core VA forms when moving between countries to allow for linguistic differences and colloquial expression and also the need to consider cultural differences between countries—for example, how soon after bereavement a VA interview can occur. Most importantly, they strongly recommend that validation studies like theirs should be routinely done when VA procedures are applied in new countries or if the major cause of death in a country changes because of a new epidemic or health initiative. Provided this is done, write the researchers, although VA procedures can never be as accurate as proper medical certification at the time of death, they should provide important information about the causes of death for the many countries where this information would otherwise be completely missing. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0030268. • World Health Organization information on mortality and on the International Classification of Diseases • The United Nations' World Mortality Report 2005 • Information on the Tanzania Ministry of Health Adult Morbidity and Mortality Project, which used the VA procedures on which this study was based • A description of a standard VA method for investigating deaths in infants and children from the World Health Organization • The INDEPTH Network, an organization collecting health statistics from developing countries that provides standardized VA forms • MEASURE Evaluation, a USAID-funded project that, in collaboration with the US Census Bureau and the University of Queensland (Australia), supports countries to implement core VA procedures and sample/sentinel vital registration methods • The Health Metrics Network, a global collaboration focused on strengthening country health information systems to generate sound data for decision-making at country and global levels, is committed to improving sources of vital statistics and cause-of-death data