Methods and apparatus to determine probabilistic media viewing metrics

A non-transitory computer-readable medium comprising instructions that, when executed, cause a processor to at least:

• calculate a first probability for respective ones of a plurality of panelists as having viewed media based on viewing data, the viewing data including incomplete viewing data for one or more of the panelists relative to the media;
• identify respective ones of the plurality of panelists as being included in a demographic subgroup based on demographic data for the panelists;
• assign a sampling weight to each of the panelists of the plurality of panelists based on the demographic data, wherein the sampling weight assigned to each of the one or more panelists associated with the incomplete viewing data is adjusted relative to the sampling weight assigned to each of the remaining ones of the panelists of the plurality of panelists;
• and
• adjust the first probabilities for the respective ones of the plurality of panelists using the sampling weights for the respective ones of the plurality of panelists to generate adjusted first probabilities;
• and
• calculate a second probability of the demographic subgroup having viewed the media based on (a) the adjusted first probabilities for the respective ones of the plurality of panelists in the demographic subgroup and (b) the adjusted first probabilities for each of the panelists in the plurality of panelists.

A system comprising:

• means for identifying probabilities, the probability identifying means to calculate a first probability for respective ones of a plurality of panelists as having viewed media based on viewing data, the viewing data including incomplete viewing data for one or more of the panelists relative to media;
• means for assigning sampling weights, the sampling weight assigning means to:
• identify respective ones of the plurality of panelists as being included in a demographic subgroup based on demographic data for the panelists, the viewing data including the demographic data;
• and
• assign a sampling weight to each of the panelists of the plurality of panelists based on the demographic data, wherein the sampling weight assigned to each of the one or more panelists associated with the incomplete viewing data is adjusted relative to the sampling weight assigned to each of the remaining ones of the panelists of the plurality of panelists;
• and
• means for analyzing subgroups, the subgroup analyzing means to:
• adjust the first probabilities for the respective ones of the plurality of panelists using the sampling weights for the respective ones of the plurality of panelists to generate adjusted first probabilities;
• and
• calculate a second probability of the demographic subgroup having viewed the media based on (a) the adjusted first probabilities for the respective ones of the plurality of panelists in the demographic subgroup and (b) the adjusted first probabilities for each of the panelists in the plurality of panelists.