Volcanic Ash Advisory Centers (VAAC) have been running forecast dispersion models and issuing Volcanic Ash Advisories for years, however only limited model evaluation has been done. A more thorough quantitative dispersion model evaluation of many volcanic eruptions is needed for several purposes: to know the model's accuracy and make users aware of the accuracy, to determine the level of sensitivity of various model inputs to the model results, to confirm that model upgrades provide better forecasts, and to aide in the interpretation of dispersion model results. An evaluation database should have the following components: (1) eruption source parameters (ESP), also called the “source term”, including volcano latitude and longitude, eruption start and stop time(s), eruption column height and mass eruption rate vs. time, etc., (2) ash observations from space, ground, and/or airborne platforms vs. time (spatial location and/or quantitative measurements), (3) archived analysis meteorology, and (4) a set of statistical model evaluation programs. The multi-disciplinary aspect of compiling these database components, for volcanoes throughout a VAAC's area of responsibility, or around the world, makes development of such a database a challenge. Descriptions of quantitative dispersion model evaluation from ground-level releases of controlled inert tracer gases and from wildfire smoke will be provided, since they may form a basis for the application to volcanic ash. Statistical measures for these near-ground-level applications include the “Figure of Merit in Space” and the “Measure of Effectiveness.”