What is Sampling Frame? Also describe errors

Sampling Frame
A sampling frame can be defined as the list consisting of the units of the population. One very necessary and critical point to be kept in mind in case of the sampling frame is that it should be made up to date and also it should be free from the various errors of the omission and duplication of the sampling units. In many cases, it has been observed that the preparation of the sampling frame sometimes becomes a very critical practical problem.

A perfect frame is the one that is able to identify each element only once and these frames are very rarely available in the real life.
A sampling frame may consist of different types of defects and these defects can be classified on the following lines:-

(a) Incomplete frame –
• Some legitimate sampling units of the population are omitted.

(b) Inaccurate frame –
• Some of the sampling units of the population are inaccurately listed.
• Or sometimes such units are involved which actually are not existing.

(c) Inadequate frame –
• Does not include all the units of the population by its structure.

Types of Errors
1. Sampling errors –
• Defined as the difference between the results got from the samples and those that would have been obtained from the complete enumeration of the population.
• Mainly arise due to the random factors.
• Occur due to the sample surveys.
• Have no error in the survey technique.
• Increase by reducing the size of the sample.
• Such an error arises when the sample represents only the part of the population.

2. Non Sampling errors –
• Occur in the survey method as well as the sample survey.
• Arise mainly due to the presence of bias.
• Also arise due to the mistakes committed by an individual, machine etc.
• Such errors increase with the increasing size of the sample.