Methods and apparatus to perform identity matching across audience measurement systems
Methods, apparatus, systems and articles of manufacture to perform identity matching across audience measurement systems are disclosed. An example apparatus includes a data normalizer to normalize audience measurement events corresponding to media exposure data obtained from a first audience measurement system and a second audience measurement system, a tree builder to build a k-dimensional tree based on normalized audience measurement events, a candidate identifier to calculate a distance between a query event and a first audience measurement event included in a search space in the k-dimensional tree, identify the query event and the first audience measurement event as a candidate match when the calculated distance satisfies a distance threshold, an array builder to generate metrics at an identifier-level based on a plurality of candidate matches, and a thresholder to identify an identifier mapping linking a first user identifier to a second user identifier when the metrics satisfy respective metric thresholds.
1. An apparatus to perform identity matching, the apparatus comprising:
memory including machine readable instructions; and
processor circuitry to execute the instructions to:
build a data structure based on normalized audience measurement events corresponding to a first audience measurement system, the data structure including a plurality of search spaces;
identify a search space in the data structure based on a query event corresponding to a second audience measurement system;
determine the query event and a first audience measurement event in the search space are a candidate match when a distance between the query event and the first audience measurement event satisfies a threshold; and
link a first user identifier associated with the first audience measurement system to a second user identifier associated with the second audience measurement system based on a plurality of candidate matches.
2. The apparatus as defined in claim 1 , wherein the processor circuitry is to:
generate a first matrix based on normalized audience measurement events corresponding to the first audience measurement system; and
generate a second matrix based on normalized audience measurement events corresponding to the second audience measurement system.
3. The apparatus as defined in claim 2 , wherein a size associated with the first matrix corresponds to (1) a number of normalized audience measurement events corresponding to the first audience measurement system and (2) a number of variables in common between the normalized audience measurement events corresponding to the first audience measurement system and the normalized audience measurement events corresponding to the second audience measurement system.
4. The apparatus as defined in claim 3 , wherein the processor circuitry is to:
compare the size associated with the first matrix to a size associated with the second matrix; and
determine whether the size associated with the first matrix is greater than the size associated with the second matrix when building the data structure based on the normalized measurement events corresponding to the first audience measurement system.
5. The apparatus as defined in claim 1 , wherein the processor circuitry is to:
build a first array based on a number of matched events between a first set of user identifiers associated with the first audience measurement system and a second set of user identifiers associated with the second audience measurement system, the first set of user identifiers and the second set of user identifiers included in the plurality of candidate matches;
build a second array based on a first percentage of matched events associated with the first set of user identifiers;
build a third array based on a second percentage of matched events associated with the second set of user identifiers; and
build a fourth array based on clock offsets associated with the plurality of candidate matches.
6. The apparatus as defined in claim 5 , wherein the processor circuitry is to:
compare a first value associated with an identifier combination from the first array to a first threshold, the identifier combination (1) selected from the first set of user identifiers and the second set of user identifiers and (2) associated with a non-zero cell in the first array;
compare a first value associated with the identifier combination from the first array to a first threshold;
compare a second value associated with the identifier combination from the second array to a second threshold when the first value satisfies the first threshold;
compare a third value associated with the identifier combination from the third array to a third threshold when the second value satisfies the second threshold; and
compare a fourth value associated with the identifier combination from the fourth array to a fourth threshold when the third value satisfies the third threshold.
7. The apparatus as defined in claim 6 , wherein the processor circuitry is to use the identifier combination to link the first user identifier associated with the first audience measurement system to the second user identifier associated with the second audience measurement system when the fourth value satisfies the fourth threshold.
8. A method to perform identity matching, the method comprising:
building, by executing an instruction with a processor, a data structure based on normalized audience measurement events corresponding to a first audience measurement system, the data structure including a plurality of search spaces;
identifying, by executing an instruction with the processor, a search space in the data structure based on a query event corresponding to a second audience measurement system;
determining, by executing an instruction with the processor, the query event and a first audience measurement event in the search space are a candidate match when a distance between the query event and the first audience measurement event satisfies a threshold; and
linking, by executing an instruction with the processor, a first user identifier associated with the first audience measurement system to a second user identifier associated with the second audience measurement system based on a plurality of candidate matches.
9. The method as defined in claim 8 , further including:
generating a first matrix based on normalized audience measurement events corresponding to the first audience measurement system; and
generating a second matrix based on normalized audience measurement events corresponding to the second audience measurement system.
10. The method as defined in claim 9 , wherein a size associated with the first matrix corresponds to (1) a number of normalized audience measurement events corresponding to the first audience measurement system and (2) a number of variables in common between the normalized audience measurement events corresponding to the first audience measurement system and the normalized audience measurement events corresponding to the second audience measurement system.
11. The method as defined in claim 10 , wherein the building of the data structure includes:
comparing the size associated with the first matrix to a size associated with the second matrix; and
determining whether the size associated with the first matrix is greater than the size associated with the second matrix.
12. The method as defined in claim 8 , further including:
building a first array based on a number of matched events between a first set of user identifiers associated with the first audience measurement system and a second set of user identifiers associated with the second audience measurement system, the first set of user identifiers and the second set of user identifiers included in the plurality of candidate matches;
building a second array based on a first percentage of matched events associated with the first set of user identifiers;
building a third array based on a second percentage of matched events associated with the second set of user identifiers; and
building a fourth array based on clock offsets associated with the plurality of candidate matches.
13. The method as defined in claim 12 , further including:
comparing a first value associated with an identifier combination from the first array to a first threshold, the identifier combination (1) selected from the first set of user identifiers and the second set of user identifiers and (2) associated with a non-zero cell in the first array;
in response to determining that the first value satisfies the first threshold, comparing a second value associated with the identifier combination from the second array to a second threshold;
in response to determining that the second value satisfies the second threshold, comparing a third value associated with the identifier combination from the third array to a third threshold; and
in response to determining that that the third value satisfies the third threshold, comparing a fourth value associated with the identifier combination from the fourth array to a fourth threshold.
14. The method as defined in claim 13 , further including using the identifier combination to link the first user identifier associated with the first audience measurement system to the second user identifier associated with the second audience measurement system when the fourth value satisfies the fourth threshold.
15. A tangible computer readable storage medium comprising instructions that, when executed, cause a machine to at least:
build a data structure based on normalized audience measurement events corresponding to a first audience measurement system, the data structure including a plurality of search spaces;
identify a search space in the data structure based on a query event corresponding to a second audience measurement system;
determine the query event and a first audience measurement event in the search space are a candidate match when a distance between the query event and the first audience measurement event satisfies a threshold; and
link a first user identifier associated with the first audience measurement system to a second user identifier associated with the second audience measurement system based on a plurality of candidate matches.
16. The tangible computer readable storage medium as defined in claim 15 , wherein the instructions further cause the machine to:
generate a first matrix based on normalized audience measurement events corresponding to the first audience measurement system; and
generate a second matrix based on normalized audience measurement events corresponding to the second audience measurement system.
17. The tangible computer readable storage medium as defined in claim 16 , wherein a size associated with the first matrix corresponds to (1) a number of normalized audience measurement events corresponding to the first audience measurement system and (2) a number of variables in common between the normalized audience measurement events corresponding to the first audience measurement system and the normalized audience measurement events corresponding to the second audience measurement system.
18. The tangible computer readable storage medium as defined in claim 17 , wherein the instructions further cause the machine to:
compare the size associated with the first matrix to a size associated with the second matrix; and
determine whether the size associated with the first matrix is greater than the size associated with the second matrix when building the data structure based on the normalized measurement events corresponding to the first audience measurement system.
19. The tangible computer readable storage medium as defined in claim 15 , wherein the instructions further cause the machine to:
build a first array based on a number of matched events between a first set of user identifiers associated with the first audience measurement system and a second set of user identifiers associated with the second audience measurement system, the first set of user identifiers and the second set of user identifiers included in the plurality of candidate matches;
build a second array based on a first percentage of matched events associated with the first set of user identifiers;
build a third array based on a second percentage of matched events associated with the second set of user identifiers; and
build a fourth array based on clock offsets associated with the plurality of candidate matches.
20. The tangible computer readable storage medium as defined in claim 18 , wherein the instructions further cause the machine to:
compare a first value associated with an identifier combination from the first array to a first threshold, the identifier combination (1) selected from the first set of user identifiers and the second set of user identifiers and (2) associated with a non-zero cell in the first array;
compare a first value associated with the identifier combination from the first array to a first threshold;
compare a second value associated with the identifier combination from the second array to a second threshold when the first value satisfies the first threshold;
compare a third value associated with the identifier combination from the third array to a third threshold when the second value satisfies the second threshold;
compare a fourth value associated with the identifier combination from the fourth array to a fourth threshold when the third value satisfies the third threshold; and
use the identifier combination to link the first user identifier associated with the first audience measurement system to the second user identifier associated with the second audience measurement system when the fourth value satisfies the fourth threshold.