Yes, the sleep algorithms used in the Philips health watch have been validated for a research version of the health watch. This research is currently in the process of being prepared for publication. More can be found here.
(http://incenter.medical.philips.com/doclib/enc/12916038/WeST_relevant_Philips_publications.pdf%3ffunc%3ddoc.Fetch%26nodeid%3d12916038)
Please note, the sleep module algorithms are not suitable for people with sleep apnea or insomnia.
