Reasons For Impracticality Of Census

There are certain reasons that make census impractical or even impossible. The reasons are as follows:

1. Cost: Cost is an obvious constraint on the determination of whether a census should be taken. If information is desired on grocery purchase and use behavior (frequencies and amounts of purchase of each product category, average amount kept at home and the like) and the population of interest is all households in a country, the cost will preclude a census being taken. Thus a sample is the only logical way of obtaining new data from a population of this size.

2. Time: The kind of cost we have just considered is an outlay cost. The time involved in obtaining information from either a census or a sample involves the possibility of also incurring an opportunity cost. That is, the decision until information is obtained may result in smaller gain or a larger loss than would have been the case from making the same decision earlier. The opportunity to make more (or save more. as the case may be) is, therefore, foregone.

3- Accuracy: A study using a census, by definition, contains no sampling error. A study using a sample may involve sampling error in addition to other types of error. Other things being equal, a census will provide more accurate data than a sample. However it has been argued that a more accurate estimate of the population of a country could be made from a sample than from a census. Taking a census of a population on a “mail out – mail back” basis requires that the names and addresses of almost all households be obtained, census questionnaires mailed, and interviews conducted of those not responding. The questionnaires are sent to a population of which only about half have completed high school. The potential for errors in a returned questionnaire is therefore high.

4. Destructive nature of the measurement: Measurements are sometimes destructive in nature. When they are, it is apparent that taking a census would usually defeat the purpose of a measurement. If one were producing firecrackers, electrical fuses, or gas seed, performing a functional use test on a all products for quality control purposes would not be considered from an economic standpoint. A sample is then the only practical choice. On the other hand, if the light bulbs, bicycles, or electrical appliances are to be tested, a 100% sample (census) may be entirely reasonable.