Census can be classified as

Analyze the question: It asks how a census (a count of a country's population) can be classified. The key is the method used to count people.

Explain the concept: There are two main ways of conducting a census:

1. De facto census: People are counted where they are physically found on census night, regardless of where they normally live. It is also called the "actual presence" method.
2. De jure census: People are counted at their usual or legal place of residence, even if they are away on census night. It is also called the "usual residence" method.

Check the options:

• A. de facto and de jure: These are the two recognised types of census. ✔
• B. increasing and decreasing: These describe population trends, not census types. ✘
• C. over and under: These describe over-population and under-population, which relate to the population's size compared with resources. ✘
• D. optimum: This refers to the optimum population, the ideal size for maximum output per head. It is not a census classification. ✘

Answer: The correct option is A.

Exam tip: Remember "De facto = Found here; De jure = Just lives here (legal residence)." Also, whenever you see over, under, optimum in Economics, think population size, not census type.