Microarray data quality is an issue that has been covered extensively in The Scientist (see, for instance, here and here). The basic issue is this: how reliable are the sometimes-subtle changes in gene expression levels these experiments yield, and how reproducible are they.
The External RNA Controls Consortium, an ad-hoc group with approximately 70 members from private, public, and academic organizations formed in 2003, is one of several groups working to address these questions. The Consortium?s goal is to develop a reference set of external RNA control (or ?spike?) transcripts, informatics tools, and procedures that can be used to assess technical performance in gene expression assays like microarrays and quantitative, real-time RT-PCR.
If that sounds boring, it shouldn't: the upshot is greater confidence in gene expression data, not to mention the potential for accelerated regulatory approval of microarray diagnostics and accreditation of testing labs.
Recently the consortium released for comment ...