Morbidity and Mortality Indicators · 50 MCQs
NEET PG-style questions. Tap an option: you are marked instantly and every option is explained, including why the wrong ones are wrong.
In a school survey, 45 of 300 children examined had scabies, and the result was reported as 15%.
Which feature makes this measure a proportion?
Why B is correct: A proportion relates a part to the whole: the 45 children with scabies are themselves among the 300 examined. That is why it is usually expressed as a percentage.
Ruling out the others:
- A. A time dimension is what makes a measure a rate. This count was taken at one point in time.
- C. The multiplier is a matter of convenience (100, 1,000, 100,000) and does not define the type of measure.
- D. The mid-year population is the usual denominator of annual rates, and this measure has none.
Four indicators are listed in a district health report.
In which of them is the numerator NOT a part of the denominator?
Why C is correct: Doctors are not a subset of the population they serve in this comparison (one doctor per so many people). The two quantities are separate, which is the defining feature of a ratio.
Ruling out the others:
- A. The people who die are part of the mid-year population, so the numerator sits inside the denominator.
- B. Deaths from one cause are part of total deaths. This is a proportion.
- D. Existing cases are part of the population examined. Prevalence is a proportion, even though it is often called a rate.
Annual death and birth rates use the mid-year population as their denominator.
On which date is the mid-year population estimated?
Why C is correct: Births, deaths and migration change the population every day. The estimate at the middle of the year (1 July) approximates the average population exposed over the whole year.
Ruling out the others:
- A. 1 January is the start of the calendar year and understates the population exposed later in the year if it is growing.
- B. 1 April is a quarter-year point and has no conventional use as a denominator.
- D. 31 December is the end of the year and overstates the average exposure in a growing population.
In an occupational cohort, 20 workers were followed for 5 years each, 10 workers for 3 years each and 10 workers for 1 year each, because they joined at different times.
How many person-years of observation does this cohort contribute?
Why C is correct: Person-years is the sum of each person's time under observation: (20 × 5) + (10 × 3) + (10 × 1) = 100 + 30 + 10 = 140 person-years.
Ruling out the others:
- A. 40 is the number of persons. It ignores time altogether.
- B. 120 comes from multiplying 40 persons by the simple average of the three follow-up times (3 years), which ignores that the groups differ in size.
- D. 200 assumes all 40 workers were followed for the full 5 years.
A district cancer registry wants the annual incidence rate of carcinoma prostate.
Which denominator should it use?
Why B is correct: The denominator must be the population at risk, meaning those who could develop the condition. Only males have a prostate, so the denominator is the male population.
Ruling out the others:
- A. Including women, who cannot develop the disease, dilutes the rate.
- C. A hospital-attending group is a selected subset and not the population at risk in the community.
- D. All cancer cases gives a proportion of cancers (a case-mix share), not an incidence rate.
Most rates use a population denominator, but some use a count of events instead.
Which indicator has a denominator made of events rather than of population?
Why C is correct: The case fatality rate divides deaths by the number of cases of the same disease, so its denominator is a count of events. The infant mortality rate (per live births) is another example.
Ruling out the others:
- A. Crude death rate is deaths per 1,000 mid-year population.
- B. Age-specific death rate is deaths in an age group per 1,000 population of that age group.
- D. Incidence rate is new cases per population at risk.
A town with a mid-year population of 80,000 recorded 60 deaths in January.
What is the death rate for January, expressed so that it can be compared with the annual death rate (per 1,000)?
Why B is correct: Monthly deaths are multiplied by 12 so that they are comparable with an annual rate: (60 × 12 ÷ 80,000) × 1,000 = 9.0 per 1,000 per year. (The convention is to multiply monthly deaths by 12 and weekly deaths by 52.)
Ruling out the others:
- A. 0.75 is the raw January figure without annualising (60 ÷ 80,000 × 1,000).
- C. 39.0 uses the weekly factor (× 52) on a monthly count.
- D. 90.0 annualises correctly but uses a multiplier of 10,000 instead of 1,000.
A district had 140,000 people on 1 January and 150,000 on 1 July, and it recorded 1,200 deaths during the year.
What is its crude death rate per 1,000?
Why B is correct: Crude death rate = deaths in the year ÷ mid-year population × 1,000 = 1,200 ÷ 150,000 × 1,000 = 8.0 per 1,000.
Ruling out the others:
- A. 0.8 uses a multiplier of 100 instead of 1,000.
- C. 8.6 uses the 1 January population (1,200 ÷ 140,000 × 1,000) rather than the mid-year population.
- D. 80.0 uses a multiplier of 10,000.
Two cholera outbreaks are compared by the ratio of deaths to cases.
Which property of the disease does this ratio represent?
Why D is correct: Case fatality rate is deaths from a disease ÷ cases of that disease × 100. It represents the killing power (severity) of the disease and is closely related to virulence.
Ruling out the others:
- A. Communicability is measured by the secondary attack rate.
- B. Infectivity is the ability to invade and multiply in a host, and it is not captured by deaths among cases.
- C. Burden relative to other causes is shown by the proportional mortality rate or by prevalence.
In a cholera outbreak in a block of 12,000 people, 300 cases occurred and 24 of these patients died.
What is the case fatality rate?
Why D is correct: CFR = deaths ÷ cases × 100 = 24 ÷ 300 × 100 = 8%.
Ruling out the others:
- A. 0.2% divides deaths by the whole population (24 ÷ 12,000), which is a cause-specific death rate and not CFR.
- B. 2.5% is cases ÷ population (300 ÷ 12,000), which is the attack rate of the outbreak.
- C. 7.4% wrongly adds the deaths to the denominator (24 ÷ 324). The deaths are already among the 300 cases.
Unlock the full paper free.
Create your free GM4T account once. It also opens the complete CM 7 dashboard.
- ✅ All 40 remaining MCQs, with ruling-out explanations
- ✅ Your score and your weak topics
- ✅ New free papers as each competency goes live