Why there is differences in the number of links connected to the same property?

Question

I have noticed that there are a different number of triples using the same property (e.g., isbn) about a Book, but coming from different sources. For instance,

Total http://dbpedia.org/property/isbn links are 20885 while
Total http://dbpedia.org/ontology/isbn links are 21132.

Why do these numbers differ? I want to know which is suitable for good information gain.

Answer 1

Although they have similar names, and represent roughly the same information, the properties are not the same. One is “http://dbpedia.org/property/isbn” and the other is “http://dbpedia.org/ontology/isbn”.

Section 4.3 Infobox Data from the DBpedia wiki says that properties from the http://dbpedia.org/property/ namespace contain raw infobox data and are used in the older Infobox Dataset:

Extracted information is represented using properties in the http://dbpedia.org/property/ namespace. The names of the these properties directly reflect the name of the Wikipedia infobox property. Property names are not cleaned or merged. Property types are not part of a subsumption hierarchy and there is no consistent ontology for the infobox dataset.

It also says that the newer Infobox Ontology uses properties in the http://dbpedia.org/ontology/ namespace:

Properties are represented using properties following the http://dbpedia.org/ontology/{propertyname} naming schema.

While the Infobox Ontology does not contain quite as much information as the Infobox Dataset, the information is much cleaner:

Therefore, the instance data within the infobox ontology is much cleaner and better structured than the Infobox Dataset, but currently doesn't cover all infobox types and infobox properties within Wikipedia.

In this case, however, it looks like there are more triples using the ontology property than the dataset property, so you should get cleaner, more consistent data using http://dbpedia.org/ontology/isbn instead of http://dbpedia.org/property/isbn.