  This paper describes methodological details used by WHO in 2015 to estimate
TB incidence, prevalence and mortality. Incidence and mortality are
disaggregated by HIV status, age and sex. Methods to derive MDR-TB burden
indicators are detailed. Four main methods were used to derive incidence: (i)
case notification data combined with expert opinion about case detection gaps
(120 countries representing 51% of global incidence); (ii) results from
national TB prevalence surveys (19 countries, 46% of global incidence); (iii)
notifications in high-income countries adjusted by a standard factor to account
for under-reporting and underdiagnosis (73 countries, 3% of global incidence)
and (iv) capture-recapture modelling (5 countries, 0.5% of global incidence).
Prevalence was obtained from results of national prevalence surveys in 21
countries, representing 69% of global prevalence). In other countries,
prevalence was estimated from incidence and disease duration. Mortality was
obtained from national vital registration systems of mortality surveys in 129
countries (43% of global HIV-negative TB mortality). In other countries,
mortality was derived indirectly from incidence and case fatality ratio.
