The Invertebrate Data Analysis System (IDAS) software provides an accurate, consistent, and efficient mechanism for analyzing invertebrate data collected as part of the National Water-Quality Assessment Program and stored in the Biological Transactional Database (Bio-TDB). The IDAS software is a stand-alone program for personal computers that run Microsoft (MS) Windows?. It allows users to read data downloaded from Bio-TDB and stored either as MS Excel? or MS Access? files. The program consists of five modules. The Edit Data module allows the user to subset, combine, delete, and summarize community data. The Data Preparation module allows the user to select the type(s) of sample(s) to process, calculate densities, delete taxa based on laboratory processing notes, combine lifestages or keep them separate, select a lowest taxonomic level for analysis, delete rare taxa, and resolve taxonomic ambiguities. The Calculate Community Metrics module allows the user to calculate over 130 community metrics, including metrics based on organism tolerances and functional feeding groups. The Calculate Diversities and Similarities module allows the user to calculate nine diversity and eight similarity indices. The Data export module allows the user to export data to other software packages and produce tables of community data that can be imported into spreadsheet and word-processing programs. Though the IDAS program was developed to process invertebrate data downloaded from USGS databases, it will work with other data sets that are converted to the USGS (Bio-TDB) format. Consequently, the data manipulation, analysis, and export procedures provided by the IDAS program can be used by anyone involved in using benthic macroinvertebrates in applied or basic research.
