Methods and apparatus to determine media exposure of a panelist

A method comprising:

• determining that census data corresponding to a panelist includes first media data that is not included in media monitoring data for the panelist during a first time period;
• responsive to determining that the census data corresponding to the panelist includes first media data that is not included in the media monitoring data for the panelist, generating backfilled media monitoring data for the panelist by supplementing the media monitoring data for the panelist during the first time period with the first media data;
• determining, based on media data in at least one of the census data and the media monitoring data, that the panelist is associated with simultaneous exposure to multiple distinct media sources during a second time period;
• and
• responsive to determining that the panelist is associated with simultaneous exposure to multiple distinct media sources during the second time period, augmenting the backfilled media monitoring data for the panelist to indicate that the second time period included simultaneous media exposures to multiple distinct media sources.

A non-transitory computer readable storage medium having stored therein instructions which, upon execution by at least one processor, cause performance of a set of operations comprising:

• determining that census data corresponding to a panelist includes first media data that is not included in media monitoring data for the panelist during a first time period;
• responsive to determining that the census data corresponding to the panelist includes first media data that is not included in the media monitoring data for the panelist, generating backfilled media monitoring data for the panelist by supplementing the media monitoring data for the panelist during the first time period with the first media data;
• determining, based on media data in at least one of the census data and the media monitoring data, that the panelist is associated with simultaneous exposure to multiple distinct media sources during a second time period;
• and
• responsive to determining that the panelist is associated with simultaneous exposure to multiple distinct media sources during the second time period, augmenting the backfilled media monitoring data for the panelist to indicate that the second time period included simultaneous media exposures to multiple distinct media sources.