@UNPUBLISHED{Scharpf2009, author = {Robert B Scharpf and Ingo Ruczinski and Benilton Carvalho and Betty Doan and Aravinda Chakravarti and Rafael Irizarry}, title = {A multilevel model to address batch effects in copy number estimation using SNP arrays}, month = {May}, year = {2009}, url={http://www.bepress.com/cgi/viewcontent.cgi?article=1193&context=jhubiostat} } @ARTICLE{Carvalho2007a, author = {Benilton Carvalho and Henrik Bengtsson and Terence P Speed and Rafael A Irizarry}, title = {Exploration, normalization, and genotype calls of high-density oligonucleotide SNP array data.}, journal = {Biostatistics}, year = {2007}, volume = {8}, pages = {485--499}, number = {2}, month = {Apr}, abstract = {In most microarray technologies, a number of critical steps are required to convert raw intensity measurements into the data relied upon by data analysts, biologists, and clinicians. These data manipulations, referred to as preprocessing, can influence the quality of the ultimate measurements. In the last few years, the high-throughput measurement of gene expression is the most popular application of microarray technology. For this application, various groups have demonstrated that the use of modern statistical methodology can substantially improve accuracy and precision of the gene expression measurements, relative to ad hoc procedures introduced by designers and manufacturers of the technology. Currently, other applications of microarrays are becoming more and more popular. In this paper, we describe a preprocessing methodology for a technology designed for the identification of DNA sequence variants in specific genes or regions of the human genome that are associated with phenotypes of interest such as disease. In particular, we describe a methodology useful for preprocessing Affymetrix single-nucleotide polymorphism chips and obtaining genotype calls with the preprocessed data. We demonstrate how our procedure improves existing approaches using data from 3 relatively large studies including the one in which large numbers of independent calls are available. The proposed methods are implemented in the package oligo available from Bioconductor.}, doi = {10.1093/biostatistics/kxl042}, institution = {Department of Biostatistics, Johns Hopkins University, Baltimore, MD 21205, USA.}, keywords = {Algorithms; Alleles; Data Interpretation, Statistical; Genotype; Humans; Oligonucleotide Array Sequence Analysis; Oligonucleotides; Polymorphism, Single Nucleotide}, owner = {rscharpf}, pii = {kxl042}, pmid = {17189563}, timestamp = {2008.08.07}, url = {http://dx.doi.org/10.1093/biostatistics/kxl042} }