The Power Atlas is a web-based resource to assist investigators in the planning and design of microarray and expression based experiments. This software is currently aimed at estimating the power and sample size for a two group comparison based upon pilot data. The methods underlying the web site are reported in Gadbury et al (2004) and the software is described in further detail at Page et al (2006).
Click here to use your own dataset.
In 2006, we downloaded the 1,080 datasets in the Gene Expression Omnibus (GEO) and processed each of them with our power analysis software. For many years, investigators could search among the datasets for the experiment that most closely resembled their proposed project and get sample size and power estimates.
Unfortunately, due to lack of funding we were not able to refresh the database against GEO on a regular basis and in 2013 due to an incompatibility with a server software upgrade for security patches and bug fixes, we made the tough decision to disable the database search until further notice.
You can still analyze datasets from GEO, but you will need to conduct the hypothesis test for the comparison of interest yourself and upload the p-values here to estimate power.
If this is your first visit, you may want to read these printer-friendly instructions for using the Power Atlas.