What is verbal autopsy?

If someone dies without any medical attention, there is often a problem of determining what the cause of death was. WHO estimates that around 40 million deaths each year are uncertified. Verbal autopsy is a process which has been in use for many years, particularly in poorer societies where many deaths don't have a cause assigned, in which an interviewer visits family or friends of the deceased person after the death, and gathers information about what happened. WHO has produced standard questionnaires for undertaking verbal autopsies.

Have the InterVA models been validated?

To a reasonable degree, yes! You can find details of various evaluations under more info. For example, a large co-validation study between actual deaths processed with InterVA and Global Burden of Disease estimates of cause-specific mortality showed high concordance (Lancet Global Health 2016; 4:e785). But it is important to recognise that there is no absolute gold standard cause-of-death data that can be used to validate verbal autopsies, and many studies have shown major differences between medical certificates and full autopsies anyway. What is important for any cause of death process is to address the question "is it good enough?" and "is it consistent?".

What is the difference between physician-coded and computer-coded VA?

Once the basic VA interview has been done, next steps can either involve physicians looking at the interview data case-by-case, and assigning causes of death, or the whole dataset can be fed into a model like InterVA-5 to automatically assign causes of death. Physician coding is slow and expensive, and there are worries about consistency between physicians and over time. Models like InterVA-5 are fast, cheap and completely consistent. But note that neither physicians nor models will be 100% correct for all cases!

Is InterVA-4 completely compatible with WHO and ICD-10 standards?

Yes, after WHO released the WHO 2012 VA standard, InterVA-4 was developed (starting from the previous InterVA-3 and InterVA-M models), and mre recently InterVA-5 has been developed to be completely consistent with the new WHO 2016 standard, as well as accepting data inputs from the WHO 2012 and SmartVA tools. InterVA-5 is consistent with WHO 2016 both for the inputs (basically the questions from the VA interview) and the outputs (ICD-10 codes grouped by WHO into VA cause categories that cover the whole of ICD-10).