DBpedia Release Evaluation
The Quality Assessment Framework (QAF) is developed to document the quality of the knowledge base and furthermore the progress of DBpedia's extraction framework. The main idea of the QAF is a comparison between a manually created best-case dataset (Gold Standard) and the output from DBpedia's ontology based extraction. The QAF estimates the precision of the extraction framework and the completeness (recall) of DBpedia compared to its source Wikipedia.
Sample Data / Gold Standard
For a significant evaluation, only potentially extractable triples are considered. Only if a triple arise from a mapped property it can be extracted. Here this triples are called mapped triples.
The following table shows the number of mapped triples, the total number of triples in the Gold Standard and the percentage of mapped triples for each category. The categories result from different patterns in which the information is given in Wikipedia infoboxes. The number of cases differ in a high extent depending on the category. The results for the categories based on small numbers should be handled with care.
Completeness / Recall (fixed mappings from 3.5.1)
| Category
|
Mapped Triples
|
Triples
|
%
|
| Total
|
1504
|
3221
|
46.7
|
| Plain Property
|
514
|
893
|
57.6
|
| Number-Unit
|
51
|
76
|
67.1
|
| Coordinate
|
36
|
54
|
66.7
|
| Interval
|
22
|
31
|
71.0
|
| List
|
478
|
801
|
59.7
|
| One-Property-Table
|
242
|
447
|
54.1
|
| Multi-Poprty-Table
|
83
|
625
|
13.3
|
| Open Property
|
13
|
139
|
9.4
|
| Open Property Table
|
0
|
26
|
0.0
|
| Internal Template
|
58
|
116
|
50.0
|
| Merged Properties
|
7
|
13
|
53.8
|
Evaluation Results
Completeness / Recall (fixed mappings from 3.5.1)
| Category
|
Cases
|
DBpedia 3.5.1
|
DBpedia 3.6
|
DBpedia 3.7
|
| Total
|
1504
|
45,7%
|
60,2%
|
61,8%
|
| Plain Property
|
514
|
80,5%
|
83,7%
|
86,0%
|
| Number-Unit
|
51
|
68,6%
|
68,6%
|
66,7%
|
| Coordinate
|
36
|
100,0%
|
100,0%
|
100,0%
|
| Interval
|
22
|
72,7%
|
68,2%
|
72,7%
|
| List
|
478
|
33,9%
|
75,7%
|
77,8%
|
| One-Property-Table
|
242
|
5,4%
|
5,8%
|
5,8%
|
| Multi-Poprty-Table
|
83
|
0,0%
|
0,0%
|
0,0%
|
| Open Property
|
13
|
23,1%
|
23,1%
|
30,8%
|
| Open Property Table
|
0
|
na
|
na
|
na
|
| Internal Template
|
58
|
8,6%
|
10,3%
|
10,3%
|
| Merged Properties
|
7
|
57,1%
|
57,1%
|
71,4%
|
Precision (fixed mappings from 3.5.1)
| Category
|
DBpedia 3.5.1
|
DBpedia 3.6
|
DBpedia 3.7
|
| Total
|
91,2%
|
92,3%
|
92,4%
|
| Plain Property
|
96,3%
|
96,6%
|
97,4%
|
| Number-Unit
|
85,4%
|
85,4%
|
85,0%
|
| Coordinate
|
100,0%
|
100,0%
|
100,0%
|
| Interval
|
100,0%
|
100,0%
|
88,9%
|
| List
|
91,5%
|
92,8%
|
93,2%
|
| One-Property-Table
|
32,5%
|
36,8%
|
34,1%
|
| Multi-Poprty-Table
|
na
|
na
|
na
|
| Open Property
|
100,0%
|
100,0%
|
100,0%
|
| Open Property Table
|
na
|
na
|
na
|
| Internal Template
|
83,3%
|
75,0%
|
75,0%
|
| Merged Properties
|
80,0%
|
80,0%
|
100,0%
|
