Influence statistics: The range of statistics designed to assess the effect or the in?uence of an observation in determining results of the regression analysis. The general approach taken is to examine the changes which occur in the regression coef?cients when the observation is removed. The statistics that have been suggested differ in particular regression outcomes on which the effect of deletion is measured and the standardization used to make them comparable over the observations. All such kind of statistics can be computed from the results of the single regression using all the data.