## What is the standardized death rate?

The standardized mortality rate (SMR) is the ratio of the number of deaths observed in a population over a given period to the number that would be expected over the same period if the study population had the same age-specific rates as the standard population.

**How is Standardised death rate calculated?**

The standardised death rate, abbreviated as SDR, is the death rate of a population adjusted to a standard age distribution. It is calculated as a weighted average of the age-specific death rates of a given population; the weights are the age distribution of that population.

### Why do we standardize mortality rates?

Standardized Mortality Ratios are frequently used in epidemiology to compare different study groups, because they are easy to calculate and also because they provide an estimate of the relative risk between the standard population and the population under study.

**What is the age Standardised mortality rate?**

The age-standardized mortality rate is a weighted average of the age-specific mortality rates per 100 000 persons, where the weights are the proportions of persons in the corresponding age groups of the WHO standard population.

#### What is SMR in epidemiology?

1. Definition: STANDARDIZED MORTALITY RATIO (abbreviated SMR) is the number of observed deaths in the study population divided by the number of expected deaths (calculated from indirect adjustment) and multiplied by 100 (Lilienfeld & Stolley, 1994; Last, 2001).

**What is a directly Standardised rate?**

Direct Standardization DSR is simply a weighted mean event rate for a study population, using the group/stratum sizes of a reference population as the weighting scheme. Standardized or adjusted rates are summary index measures for the purpose of comparison only; their magnitude has no intrinsic value.

## What is standardization method?

Standardization is a method used to compare observed and expected rates of a given disease/outcome by removing the influence of factors that may confound the comparison.

**What are the methods of standardization?**

There are two major standardization methods: one is used when the available ‘standard’ is the structure of a reference population (direct method) and the other when the ‘standard’ is a set of specific event rates (indirect method).

### What is standardized rate in epidemiology?

Standardised rates are used for the comparison of two or more populations; they represent a weighted average of the age specific rates taken from a ‘standard population’ and are not actual rates.

**What is the difference between crude specific and standardized birth and death rates?**

The difference between crude rates and standardized rates is that crude rates are calculated based on the population under study as a whole whereas standardized rates are based on particular characteristic(s) as standard (Figure 1).

#### How are expected deaths calculated in SMR?

The expected number of deaths for the SMR is calculated by multiplying the number of persons in each age group of the study population by the age specific death rates of the general population in the same age groups of the study population and summing this over all age groups.

**What is the main reason for standardizing rates to a population with a standard age distribution?**

Direct standardization applies a standard age distribution to the populations being compared in order to compute summary rates indicating how overall rates would have compared if the populations had had the same age distibution.