When a failure occurs, geotechnical engineers, engineering geologists, and geophysicists assign its cause to an event that immediately precedes the failure, such as an earthquake, heavy rainfall, flood, or other natural event. Assigning the failure to the immediate event is misplaced; the metastasis occurred because marginally stable conditions were allowed to exist through substandard investigations by the technical personnel, improper design, and inadequate review by the permitting agency. The fundamental cause of the failure is human error and is manifested in one or more of six categories. (1) Before the investigation, during discussions with the client. (2) During the investigation, by collecting inadequate, incomplete, or incorrect da...