Design effect

Common card · No. 389390

In survey research, the design effect is a number that shows how well a sample of people may represent a larger group of people for a specific measure of interest (such as the mean). This is important when the sample comes from a sampling method that differs from simply picking people using a simple random sample. The design effect is a positive real number, represented by the symbol Deff {\displaystyle {\text{Deff}}} . If Deff = 1 {\displaystyle {\text{Deff}}=1} , then the sample was selected in a way that is just as good as if people were picked randomly. When Deff > 1 {\displaystyle {\text{Deff}}>1} , then inference from the data collected is not as accurate as it could have been if people were picked randomly. When researchers use complicated methods to pick their sample...

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