Abstract: An example apparatus includes means for identifying a pattern in first cookies received via the Internet and stored in a storage device, the first cookies corresponding to devices accessing media via the Internet, means for determining an error between a first demographic estimate based on a potential pattern in the first cookies and a second demographic estimate based on user identifiers corresponding to the devices and received via the Internet, the means for determining the error to determine the potential pattern to be the pattern when the error is less than a threshold, means for accessing impression information received from a database proprietor via the Internet, the impression information including second cookies, and means for identifying a subset of the second cookies that are associated with a same person based on the pattern, the means for identifying the subset to associate impressions corresponding to the identified subset with the same person.

Abstract: Example methods and apparatus to de-duplicate impression information are disclosed. An example method includes extracting, by executing a first instruction with a processor, characters from first cookies stored in a first memory space, the first cookies collected from client devices via network communications, and in response to the processor determining that at least two of the first cookies (1) include a same pattern of characters, and (2) correspond to a same first demographic, executing a second instruction with the processor to store, in a second memory space, the pattern of characters in association with the first demographic to indicate that the pattern of characters and the first demographic are both representative of a same first unique audience member.

Abstract: Methods and apparatus to correct errors in measuring audiences of over-the-top media are disclosed. In some examples, the methods and apparatus identify a first set of data from a first data source, the first set of data different from a second set of data from a second data source. In some examples, the methods and apparatus generate a third set of data based on the second set of data from the second data source. In some examples, the methods and apparatus generate a model based on a difference between the first set of data and the third set of data. In some examples, the methods and apparatus apply the model to the first set of data. In some examples, the methods and apparatus assign viewership to an impression associated with the first set of data by imputing viewership associated with the second set of data to the first set of data.

Abstract: Example methods and apparatus to de-duplicate impression information are disclosed. An example method includes extracting, by executing a first instruction with a processor, characters from first cookies stored in a first memory space, the first cookies collected from client devices via network communications, and in response to the processor determining that at least two of the first cookies (1) include a same pattern of characters, and (2) correspond to a same first demographic, executing a second instruction with the processor to store, in a second memory space, the pattern of characters in association with the first demographic to indicate that the pattern of characters and the first demographic are both representative of a same first unique audience member.

Abstract: Example methods and apparatus to de-duplicate impression information. An example method includes accessing a first set of cookies and a set of user identifiers, the cookies and user identifiers corresponding to devices accessing media via the Internet, identifying a pattern in the first set of cookies, obtaining impression information from a database proprietor, the impression information comprising a second set of cookies, identifying a subset of the second set of cookies that are associated with a same person based on the pattern, and associating impressions corresponding to the identified subset with the same person.

Abstract: Methods and apparatus to compensate impression data for misattribution and non-coverage by a database proprietor are disclosed. An example method includes obtaining a count of media impressions occurring on a first type of computing device, a first portion of the media impressions corresponding to persons for whom demographic information is recognizable by a database proprietor and a second portion of the media impressions corresponding to persons for whom demographic information is unavailable to the database proprietor; and determining the demographic information for the second portion of the media impressions based on a first probability that media corresponding to the media impressions is accessed on the first type of computing device and based on a second probability that media is accessed on a second type of device.

Abstract: Example methods and apparatus to de-duplicate impression information. An example method includes accessing a first set of cookies and a set of user identifiers, the cookies and user identifiers corresponding to devices accessing media via the Internet, identifying a pattern in the first set of cookies, obtaining impression information from a database proprietor, the impression information comprising a second set of cookies, identifying a subset of the second set of cookies that are associated with a same person based on the pattern, and associating impressions corresponding to the identified subset with the same person.