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).

If you are a current user and have found this resource useful, please get in touch with us! We are actively pursuing funding to further develop the Power Atlas by adding more datasets and methods and to continue to keep it free and up-to-date. Your letters of support will play a vital role in moving this project forward.

There are two ways to use the Power Atlas:

1. We have downloaded the datasets currently in the Gene Expression Omnibus (GEO) and processed each of them with our power analysis software. Investigators may search among the datasets for the experiment that most closely resembles their proposed project and get sample size and power estimates. These estimates are currently available for 1080 datasets. We plan to refresh the database at regular intervals, the last update was performed in June 2006 and the next refresh is scheduled for mid-2007.

Click here to search the existing database.

2. Investigators may upload their own preliminary data and the program will extrapolate power from this dataset.

Click here to use your own dataset.

If this is your first visit, you may want to read these printer-friendly instructions for using the Power Atlas.