Although standard procedures and methods are available for many aspects of geotechnical site characterization, the quality of the results of such activities can be highly variable because of a variety of factors, including limitations resulting from the test procedures. For initial projects, the nature of these limitations as well as their likely consequences can be reasonably accommodated; however, subsequent use of the same data in a late study may not have the benefit of this project-specific insight, particularly if the data have been archived in a digital database. Consequently, a technique for quantifying data quality is necessary. A geographical information system (GIS)-based methodology has been developed to allow for the evaluation of borehole log quality as a function of its intended use. The methodology uses a flexible hierarchical model to provide a quantitative measure of quality. The quality of the discrete boreholes distributed across a site can then be analyzed spatially within a GIS to provide a more complete assessment of quality for the entire project. This framework also allows for evaluation of the effect of additional borehole logs at a site and can be used to optimize such planning activities in a virtual environment.