A computer simulation program was developed to teach site investigation skills. It includes an open-ended assessment test to gauge an individual's abilities and effectiveness at site investigation. The test consists of a series of educational and experience questions followed by 14 investigation strategy questions, which were designed to measure the ability to apply geological knowledge to characterize sites and improve investigation plans. The individual scores on the test were compared statistically with the educational and experience elements to assess the critical components of an engineering geologist's background that improved his or her site investigation skills. The most important college courses contributing to site investigation skills include geomorphology, field camp, regional geology, and a strong introductory geology course. Secondary but helpful courses include case histories, stratigraphy, structural geology, engineering geology, sedimentation, rock mechanics, and hydrogeology. The total number of geology background courses is not statistically significant, nor is the terminal degree earned, although individuals with certain post-baccalaureate degrees showed higher scores than average. The number of years of experience is statistically significant, although after 20 years statistical improvements do not continue. Professional registration is correlated with improved scores, with the Certified Engineering Geologist and Geotechnical Engineer registration being the most important. Those who have only Engineer-in-Training or Geologist-in-Training registration showed significantly lower than average scores, reflecting their short record of experience. Finally, the number of geographic regions in which an individual had work experience was significant, although those who had worked in more than five regions did not follow the overall trend. Those with experience in the Rockies, California, the Piedmont, New England, and the Gulf Coast scored better than average. Those with experience in Florida, the Appalachians, or the Midwest scored worse than average, which may be a reflection of the relatively homogeneous geology and limited opportunities for breadth of experience in parts of those regions.