# Metadata Quality for Biobanks
## 6 Metadata Quality Characteristics and Metrics
### Metadata Completeness
#### 6.3.1 Related Work on Metadata Completeness  
A significant number of authors address metadata completeness in their papers:  
1. Some authors defined such completeness explicitly based on the presence of the metadata valuesKiraly et al. [40] defined completeness this way for the case of digital heritage repository,
* [PERSON] et al. ([41; 42]) defined metadata completeness this way at the field and representation levels exemplified by the detailed set of metrics,
* [PERSON] et al. [43] defined completeness of the metadata records in learning object repositories;
* [PERSON] et al. [19] defined metadata completeness by using the criteria such as \"being as complete as economically possible\", and \"completeness in covering the whole population\";
* [PERSON] et al. in the further paper [18] defined metadata completeness mostly as completeness in describing the relations between resources;
* [PERSON] et al. [17] defined metadata completeness as annotation completeness with respect to the data sources and the real world;
* [PERSON] et al. [25] defined completeness
* for the metadata records--as a degree to which the values of the properties are present in a description, as compared to the standard (e.g., to the Dublin core specification),
* for the metadata catalog--based on the number of objects with complete metadata records. * [PERSON] et al. [44] defined completeness through implementing the minimally viable record;
* [PERSON] et al. [45] defined metadata completeness as completeness representing the quality as a whole visually. * [PERSON] and [PERSON] [26] calculated completeness taking into account the relative importance of the metadata fields in a given context. * [PERSON] et al. [37] and [PERSON] et al. defined existence as a quality characteristic for open data portals understood as completeness applied to certain attributes; [PERSON] et al. [38] proposed a similar characteristic to access the quality of metadata for open government data. Some researchers treated completeness metrics in more detail:  
1. [PERSON] et al. ([41; 42]) described a set of metrics to measure metadata completeness. These metrics are fine-grained, i.e., they go down to the field level. Among these metrics: * completeness of a metadata field (differently calculated for simple, and aggregate--single-valued and multi-valued fields by traversing the metadata schema hierarchy) * completeness of a metadata record (weighted average of field completeness) * completeness at the representation level (considered as supplementary to the field completeness, reflects the additional presentation features influencing the quality, such as completeness of the set of possible audio or video illustrations)
2. [PERSON] [40] described the metrics for metadata completeness for digital heritage resources on three levels--individual records, subsets (collections), the whole datasets: * simple completeness and completeness of sub-dimensions--ratio of filled fields; * existence of fields--the ratio of available fields as compared to the source elements in a record; * uniqueness of the descriptive fields (title, alternative title, description); * multilinguality. This work also investigates the existence of record patterns--i.e., the groups of fields that form the \"typical record\". 3. [PERSON] et al. [44] identified a set of standard attributes for the metadata record (constituting a minimally viable record) and defined a quality metric for the degree of such attributes being present. * [PERSON] et al. [46] proposed another approach of applying weights to calculate the completeness of metadata elements. * [PERSON] et al. [47] split the metadata tags into four categories (compulsory, recommended, domain-specific, optional; with a possible assignment of priorities) and calculated category-specific completeness values. In the survey of opinions by metadata practitioners regarding the relative importance of metadata quality characteristics conducted by [PERSON] et al.