What is a convenience sampling?

What is convenience sampling in statistics?

• Answer:

  It is a form of nonrandom sampling. In essence it means obtaining observations that are easiest to get. For example, asking your friends how they plan to vote would be a political poll based on a convenience sample. Many types of formal, probability statistics are meaningless when convenience sampling is done. The researcher cannot claim to "generalize" their findings to any particular population. You probably could not accurately (i.e., within a couple percentage points) predict an election result based only on what your friends say. Therefore most typical statistical studies would avoid convenience sampling. It may be very useful for qualitative studies, but less so for quantitative work.