Use of Accidental Sampling

Supposing one is interested in knowing the incidence of pest infestation for a particular crop in a sizeable area. Getting interior to the crop is difficult. Investigators may decide to move around the area on the road and inspect the road side plots for pest infestation for the crop. Can they make a correct idea about the percentage of effected crop area? The answer should be ‘No’ as he has not inspected the random portion of the crop area to be inspected. The sampling method adopted is “Accidental Sampling”. It is a type of non probability sampling which involves the sample being drawn from that part of the population which is close to hand. That is, a sample selected from the population is biased one, because it is that part which is convenient to choose. The researcher using such a sample cannot scientifically make generalizations about the total population from this sample as it would not be representative enough. This accidental sampling can be adopted at best for some pilot testing or can be used to frame certain hypothesis to be tested scientifically. If some questionnaires need to be field tested, there may not be a big requirement of selecting a rigorous random sample using a population frame. Thus, for such type of work, accidental sampling can be adopted. If one has to just get a feel of public opinion on some happening around in the community at large, well framed questions can be put on even on some social site and may get the answer to the same from the public whosoever wants to give some reaction. But caution is that one should not generalize the same for the entire community.