True regarding mortality rate:
(Refer: K. Park’s Textbook of Preventive and Social medicine, 24th  edition, pg no: 63
Standardized mortality ratio

Standardized mortality ratio is the ratio of observed deaths by expected number of deaths
Standardization is usually done for age > sex in order to compare death rates between the countries
Crude death rates are estimated by SRS in India. NFHS have also given data.
Only deaths from death certificate data are not the only source.
Little important information about changing pattern of disease
Usually standardization for age and sex
Crude death rate includes only deaths from death certificate data
Standardization mortality ratio is the unexpected number of death divided by observed number of deaths in a specific group