Probability and Non  Probability Sampling

The following s are some  of the  considerations for the  selection  of probability  an non  probability  sampling.

1.Sometimes probability  considerations for  the selection probability  and non  probability  sampling: non response  is quite  high the use of probability   sampling looses its significance and non  probability  sampling  may be more appropriate.

2.When  the inquiry is to  given more objectivity and the accuracy of the investigation is to  be ensured  at some  desired level and then  the only  alternative is probability sampling.

3.Since randomness  is not  involved in non probability methods an estimate of sampling errors cannot  be made.

4. When there  are constraints of time money and availability  of appropriate sample frame   then the only  course  is non  probability sampling.  Especially in situations where  more resources are to be devoted for accurate collection of information then in  selection of the sample  units e, g,  consumer preferences  non probability  sampling is more  appropriate.

The overall  choice  between  probability  and non  probability sampling methods is a difficult is difficult exercise. The control  and measurement  of sampling  error is  probability  sampling techniques  should not be the sole  determinant of sampling procedure. The final  choice  should depend  on some  informal  judgment. The objectives of the inquiry  the nature  of the  universe resources  available  at one  disposal  may be guiding  factors in the selection  or appropriate sampling  methodology.