Tools of measurement

1. Tools of measurement

2. • The health status can be measured by using the following
tools:
• 1. Rates
• 2. Ratios and
• 3. Proportions

3. Rates
• A rate measures the incidence of some particular
event in a given population during a given time
period.
• The rate expressed per 1000 or 10,000 or 1,00,000

4. • Epidemiologic –Rate consists:
1. Numerator
2. Denominator
3. Time specification and multiplier

5. Various categories of rates are:
 Crude rates
 Specific rates

6. proportions
• Proportion indicates the magnitude of a part in relation to
the whole. The numerator is always a part of denominator.
• proportions = a/(a+b)
• Proportion in epidemiology tells us the fractions of the
population (people ) affected.

7. Ratio
• Like proportion , ratio is a fraction but without a specified
relationships between the numerator and the denominator.
• It includes two random quantities.
• Ratio is the result of dividing one quantity by another.

8. Example; occurance of hypertension
• Female cases: 240
• Male cases =120
• The ratio is= 240/120=2:1
• (female to male ratio)