Methods and apparatus to measure audience composition and recruit audience measurement panelists

A media device comprising:

• means for analyzing a video stream of media being presented by the media device, the means for analyzing to detect a first code embedded in the video stream, the first code referencing first audience measurement data to identify the media;
• and
• means for modifying a media output, the means for modifying to:
• after detection of the first code, provide a request for an audience member to join an audience measurement panel;
• and
• after receipt of a response to the request, cause the media device to present a second code, the second code including information that, when the second code is scanned with a portable device other than the media device, is to direct the portable device to a website to provide additional audience measurement data.

An apparatus comprising:

• means for storing audience measurement data associated with an audience member;
• and
• means for analyzing the audience measurement data, the means for analyzing to:
• assign a flag to the audience measurement data when panel enrollment information for the audience member is not stored in the means for storing;
• and
• when the panel enrollment information is obtained within a threshold period of time after the flag is assigned, associate the audience measurement data with the audience member.