Abstract: According to the present invention there is provided a method of analysis of the audience for channels selectable by a channel selector device for presentation on a presentation device, the channel selector device providing data indicating which channels are selected and the lengths of time for which selected channels remain selected. The data relating to the lengths of time for which channels remain selected is subject to a capping procedure, whereby the indicated length of time for which a channel remains selected is reduced to a capped maximum permitted length of time if the indicated length of time exceeds the maximum permitted length, to provide capped data.

Abstract: Audience measurement systems having fixed and portable monitoring devices are provided. Embodiments of the audience measurement system may be suitable for monitoring programs viewed and/or listened to by one or more members of a sample household. The fixed monitoring device may be associated with a particular media device, for example, in the household's home and monitor a received broadcast signal and/or a state of the media device to extract information enabling a received program and/or station to be identified. The portable monitoring device may comprise a receiver for receiving sound of a program emitted by any nearby media device; a data extractor for extracting data from the received sound to enable a program and/or station to be identified. Either a first or a second communicator may be operable to transmit a device present signal in the vicinity of its respective monitoring device, and/or detect the said signal.