Accidental sampling is a type of non-random sampling. There are many types of non-probability sampling and the selection of a technique depends on the nature and type of the study.
Process of accidental sampling
In most of the research studies the population is large. Therefore it is impossible to have all the population participate in the study. So, in every research the researcher selects a specific number of sample that can represent the characteristics of the population.
Here, in accidental sampling the researcher identifies the population and decides on the sample size. Next the researcher decides on a criteria that can help select the sample from the population. This criteria can be any depending on the ease and convenience of the researcher. The researcher may decide to select members of the population that are easily accessible, readily available, willing to participate, available in close proximity, etc. Since most of the time the researcher selects participants because of their situation and ease of access, we call it both accidental and convenience sampling. The researcher asks the respondents questions. These questions can be in the form of a questionnaire or an informal interview. Some respondents may refuse to answer and the researcher can contact another one. In all, this method of sampling is very informal and easy to conduct.
Most non-probability sampling help the researcher dig deeper and get in-depth insight into the phenomenon, same goes for this type of sampling. It provides data that can help the researcher understand the research topic more accurately. This type of sampling is always affordable, less time consuming, subjects are readily available, and easy to conduct.
Sometimes, another very important reason for the use of accidental sampling is that the population is homogeneous. The researcher believes that if he uses any other random sampling technique the results wont be much different.
Like any other non-probability sampling this sampling lacks generalizability. But, with this type of sampling you can dig deep and study what participants know about. However, the breadth of information is questionable. Hence, it is not possible to apply the findings to larger audience. Also, since, the sample is selected on a very non-random basis therefore, credibility is not accurate.
This type of sampling therefore, does not produce very formal outcomes but can be used to produce a rough estimate and understanding of the phenomenon. It lacks strategy and proper planning. It can be a starting point for any research like a pilot study.
Biases are also possible in this type of research but biases can be avoided.
The selection of any sampling method should accompany a rationale for it. Random sampling methods are preferable in many cases but they are not always possible. In those cases where randomization is not possible the researcher should provide a justification for the use of a non-formal, or non-random sampling technique.
For example, if a researcher selects accidental sampling to survey consumers in a mall what is his rationale to select sample in this way. Were there other possible sampling techniques that he could use and if he did not use any other what was the reason. This will explain that regardless of any demerits the selection of a sampling technique (like accidental sampling) is justifiable.