3.1.14 Sampling and non-sampling errors
To appreciate the need for sample surveys, it is necessary to understand clearly the role of sampling and non-sampling errors in complete enumeration and sample surveys. The errors arising due to drawing inferences about the population on the basis of few observations (sampling) is termed sampling error. Clearly, the sampling error in this sense is non-existent in complete enumeration survey, since the whole population is surveyed. However, the errors arising at the stage of ascertainment and processing of data, which are termed non-sampling errors, are common both in complete enumeration and sample surveys.