--- title: "The Jackknife" canonical: "https://modelassist.epixanalytics.com/space/EA/26575404/The%20Jackknife" format: markdown --- The Bootstrap was originally developed from a much earlier technique called the Jackknife, invented by the brilliant and practical statistician John Wilder Tukey (1915-2000). The Jackknife was used to review the robustness of a statistic calculated from a set of data. A *Jackknife value* was the statistic of interest calculated with the *i*th value removed from the data set and is given the notation ![image](media://e4ba700f-4513-4e05-b26e-6d67d9735b12) > Macro (mathinline) . With a data set of *n* values, one thus has *n* Jackknife values, the distribution of which gives a feel for the uncertainty one has about the true value of the statistic. We say "gives a feel" because the reader is certainly *not* recommended to use the Jackknife as a method for obtaining any precise estimate of uncertainty. The Jackknife turns out to be an awful estimation of uncertainty.   ### Example: The [Jacknife](#Jacknife) model performs a Jackknife analysis on a data set in an attempt to evaluate the uncertainty about the population's mean and standard deviation. A non-parametric Bootstrap is performed on the same data set, and the results of the two techniques are shown below. The Jackknife clearly provides a distribution with far too little spread.   ![image](media://cd84d8e7-b85a-40d1-bd2e-9cd9f9ab8fd3)     ![image](media://c2eb3d11-c158-4d0e-9e5f-b07e5a3a6278)   > Macro (anchor) The links to the Jacknife software specific models are provided here:
Crystal Ball > Macro (inline-media-image) [Jacknife](/wiki/download/attachments/26579343/Jacknife-CB.xlsx?version=1&modificationDate=1506113495000&cacheVersion=1&api=v2)
@Risk > Macro (inline-media-image) [Jacknife](/wiki/download/attachments/26581760/Jacknife-AtRISK.xlsx?version=1&modificationDate=1506097513000&cacheVersion=1&api=v2)
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