Snomad: Biologist-Friendly Web Tools for the Standardization and NOrmalization of Microarray Data. The use of DNA microarrays and other gene expression analysis techniques throughout the biological sciences has put extremely large, complex datasets in the hands of biologists who, for the most part, are not formally trained in computational or statistical methods. The majority of gene expression datasets have extensive artifactual bias and/or noise, which are not apparent upon superficial inspection. The SNOMAD gene expression analysis tools are an effort to make important normalization and quality control methods available to a wide audience of biological scientists working with gene expression data. Methods available in the SNOMAD tools include background subtraction, global mean normalization, local mean normalization across absolute intensity, local variance correction across absolute intensity, and ratio correction across the physical surface of the microarray. The SNOMAD web-implementation, available free of charge to all researchers at provides these tools without the downloading or installation of additional software, and does not require users to have any statistical or computer programming expertise.