The report examines the data quality achieved during a field study implemented by the EPA's Wetland Research Program (WRP) at the Environmental Research Laboratory in Corvallis, Oregon. The project was conducted by Connecticut College as part of the WRP's ongoing research on created wetlands. It was one of three pilot projects aimed at developing methods for comparing natural wetlands with created wetlands. Soils, vegetation, hydrology, and site morphology data were recorded. Root specimens were collected and tested for the presence of vescular-arbuscular mycorrhizae. In addition, each site was surveyed, mapped, and photographed. One objective of the study was to identify field procedures which correctly differentiated wetlands based on their structural characteristics. High quality field data is required to distinguish environmental differences between sites, s extensive data quality assessments were included. Wherever possible, field procedures were evaluated for data errors occurring during sample collection, data recording, sample storage, and analysis. The report outlines the data quality assessment procedures used and summarizes the results of the assessment.