how do they get there figures

[puddicat]

when they say they have such and such amount listening and viewing, radio and tv, do they know when we are tuning in lol

[Buenchico]

TV viewing figures are collected by BARB, using set-top boxes, in a representative sample of homes, which record information about the channel being watched. See here for details:
http://www.barb.co.uk/about.cfm?flag=about
(That's the first of 5 pages. Click 'Next' to read more).

Radio figures are compiled by RAJAR, using diaries kept by a sample of listeners. Click item 4, here, for further details:
http://www.rajar.co.uk/INDEX2.CFM?menuid=1

Chris