Inversion of 1D technique (VES and TDEM) by using Global Search Procedures (GSPs) as proved to be effective in evidencing local minima and equivalence problems, evaluating non-uniqueness in the solution, and estimating the values and uncertainties of the model parameters. The proposed approach is based on a Monte Carlo algorithm optimised through the application of the scale properties of the apparent resistivity curves. A statistical test selects a limited number of final models according to data uncertainties, model parameterisation and a chosen level of confidence