Convenience Sampling is a Tool for many now In the Age of Internet

It is not a probability sampling technique. Population may be very large and time and money is short to get to the public opinion. Public opinion polls are being conducted by resorting to this sampling scheme. A convenience sample is the one where its constituents or members (i.e. the sample units) that are selected for inclusion in the sample are the easiest to access or get for any survey work. This way of sampling is wide apart from the probability sampling techniques, where the selection of units is made by giving some chance of selection. For our desired sample from a population, we may be only interested in fetching a fixed or some sizeable sample size who would take part in our study of research. Many a times the sample size is also decided on the basis of convenience. As such, we normally continue to select the sample to take part in the research until our sample size was reached or try to maximize or optimize which is normally based on the time available. Some such samples are being obtained through the web along with the data on some pin pointed question(s). Some such surveys are particularity regarding the feed back or opinion from the internet users at large. Such internet users also don’t get represented objectively. It is purely who answers these polls etc. Since the aim of convenience sampling is only easy access, we may simply choose the sample by either standing at one of the main entrances or exits of a cinema hall we are interested in to have public opinion regarding whatever we choose to know about, where it would be easy to interact many cine goers to that particular cine theatre to take part in the desired survey.
Convenience sampling is resorted as it is very easy to carry out with few game rules governing how the sample should be surveyed. The relative cost and time required to carry out a convenience sample are small in comparison to probability sampling techniques. This enables you to achieve the sample size you want in a relatively fast and inexpensive way. But, the convenience sample often suffers from a number of biases as the sample will not be true representative of the population of which it is a part. It can lead to the under-representation or over-representation of particular groups within the sample. Since the population frame is not known, and the sample is not chosen at random or with some probability scheme, the sample is likely to be not representative of the population being studied. Thus, generalizations from the convenience sample can not be made for the population you are studying. In spite of these shortcomings of the convenience sampling, Reserve Bank of India had been through ages estimating Savings and Capital Formation (Investment) for the Private Corporate Sector for the National Accounts of the Country by resorting to this type of sampling. Very few annual reports of Public Limited Companies and more so for the Private Limited Companies are being used and these are the ones which are not sampled based on probability sampling technique, but are those which they had easy access to for a continuous time period. Thus, our planning is having such biases. The estimation procedures to be used for the significant component of the Economy should be based on sound statistical procedures.