Sampling and validity

ABSTRACT Sampling strategies are directly related to external validity. The choices researchers make in selecting sampling frames and sampling participants need to be clearly articulated. Sampling choices can introduce a variety of biases into research findings that reduce the external validity of samples. This essay discusses the relationship between sampling and external validity and provides a brief overview of important sampling concepts including power, the central limit theorem, nonprobability sampling and probability sampling. Sampling related biases are overviewed in the context of communication research. Finally, strategies that researchers and the discipline as a whole might adopt to ameliorate validity concerns related to sampling are proposed.