1. A method measuring attribute importance in a subsurface formation comprising: a) making a multivariate Gaussian assumption with a normal score transformation; b) executing a simple kriging to estimate a prior mean (y SK ) and variance (δ SK 2 ); c) calculating a matrix of correlation coefficients from all collocated combinations of normal scored event pairs; d) executing a simple kriging with the calculated model of multivariate correlation to estimate a likelihood mean (y L ) and variance (δ L 2 ); e) calculating an updated Gaussian Probability Distribution Function (PDF) by combining the prior and likelihood estimates according to the Gaussian normal score transformation (a); and f) transforming the updated Gaussian PDF N(y U , δ U 2 ) back to real units using the normal score transformation (a).