Definition Kurtosis

The deviation of the course of a distribution from the course of a normal distribution is called kurtosis (curvature). It indicates the sharpness or peakedness of a curve. Within this definition, it is possible to distinguish between distributions with positive excess kurtosis (tapered curve), e.g., leptokurtic distributions, and distributions with negative excess kurtosis (shallow curve), e.g., platykurtic distributions.

The kurtosis is one of the central moments of a distribution by means of which the curve is defined. A kurtosis with value 0 is mesokurtic, a kurtosis with a value greater than 0 is leptokurtic, and a kurtosis with a value less than 0 is platykurtic.

Note: Often, the terms excess and kurtosis are used interchangeably, when in fact the excess refers to the kurtosis coefficient. 

Please note that the definitions in our statistics encyclopedia are simplified explanations of terms. Our goal is to make the definitions accessible for a broad audience; thus it is possible that some definitions do not adhere entirely to scientific standards.

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