A purposive sampling is a non-random sampling in which the selection of the sample is based on person expertise about the population. As the purposive sampling is not based on the probability theory therefore, no objective method for measuring the reliability of the sample results. This technique being unscientific always involve the liking and disliking of the enumerators. This method is useful only when the sample drawn is small provided the selection of the sample is representative and the investigator is thoroughly skilled and has experience in the field of inquiry and known the drawbacks of the deliberate selection.
