Which statement about crude birth rate (CBR) and crude death rate (CDR) is true?

• A. CBR and CDR are always accurate across all age structures without adjustment
• B. CBR is births per 1,000 population and CDR is deaths per 1,000 population
• C. Age adjustment is never needed for comparing populations
• D. CBR is births per 100,000 and CDR is deaths per 100,000

Answer: (B)

The key idea here is how these crude rates are defined and what they imply for comparisons. A crude birth rate is the number of live births in a year per 1,000 people in the population, and a crude death rate is the number of deaths in a year per 1,000 people. This per-1,000 base is what makes the statement true. Crude rates are not adjusted for the age structure of the population, so differences in age distribution can distort comparisons between populations. To make fair comparisons, you would use age-adjusted (standardized) rates. The other statements are less accurate because they either imply crude rates are always precise across different age structures, claim age adjustment is never needed, or use a per-100,000 denominator, which is not the standard form for crude birth and death rates.