Census and Survey

Survey is a general term that refers to the collection of data by means of interviews, questionnaires or direct observation. The entities surveyed could from a whole ‘whole’ when it is called a census (complete count) or ‘part’ when it is called a sample survey.


A sample survey is a study involving a subset (or sample) of individuals selected from a larger population by accepted statistical methods. It is an alternative to complete count of a population serving as a basis for estimates or inferences for that population.

The census is an operation that is generally confined to inquire that are more or less straightforward counts like censuses of population, manufacturing industries, live stocks etc. while the term survey being applied to inquires which goes beyond simple counts. From this point of view, it is sensible to speak of sample census. Traditionally, a sample census is a large sample survey that is undertaken after each population census using a long questionnaire. This sample census is integrated with the population census for detailed data on such events as birth, death, marriage and migration. Almost every country Population Census also follows this practice.

Many people now regard a census as a special case of sampling when all the units of the population are included in the sample (UN, 1997). This appears to be a meaningful concept, because except for sampling error. The same sources of error that pertain to a sample also pertain to a census. In fact, non-sampling error can often be more adequately controlled when using a small sample. Therefore, the combined error from all sources is not necessarily less for a census than for a sample.