AN EXPLORATORY STUDY OF THE DESCRIPTION FIELD IN THE DIGITAL PUBLIC LIBRARY OF AMERICA

Transcription

1 AN EXPLORATORY STUDY OF THE DESCRIPTION FIELD IN THE DIGITAL PUBLIC LIBRARY OF AMERICA Hannah Tarver Oksana L. Zavalina Mark Phillips 1

2 Outline of presentation Introduction and background Methodology of the study Some findings Discussion Conclusions and future research 2 2

3 INTRODUCTION AND BACKGROUND 3

4 Description metadata Repeatable metadata elements with free-text data values One or more elements in different metadata schemes Dublin Core: Description (abstract, table of contents) Metadata Object Description Schema: Abstract, Note, Table of Contents Encoded Archival Description: Scope and Content Machine Readable Cataloging: 5XX notes (a total of 53 fields) 4

5 Description metadata: data values Best practice recommendations suggest including information about information object s: an abstract, table of contents, reference to a graphical representation of content or a free-text account of the content (DC) subject, significance, and function (CCO and CDWA) provenance and history, language (OSU Libraries) etc. 5

6 Description metadata application Inconsistent levels of application in 40%- 99% of metadata records: 50.9% in OAIster (Ward, 2003) 40-75% across university digital repositories (Kurtz, 2010) 99% in digital video collections (Weagley, Gelches, & Park, 2010) 100% in digital image collections (Park, 2006) by 72%- 89% of data providers in aggregations: 72% in OAIster (Ward, 2003) 89% in IMLS DCC aggregation (Jackson et al., 2008) 6

7 DPLA Digital Public Library of America (launched in 2013) One of the largest and rapidly growing digital repositories Distributed network model: Content hubs Service hubs 7

8 DPLA & Description Description defined in DPLA Metadata Application Profile as Includes but is not limited to: an abstract, a table of contents, or a free-text account of described resource Discrepancy in Description documentation recommended field in Intro to DPLA Data Model: version 4 (2015) optional in complete DPLA Metadata Application Profile: version 4 (2015) Metadata normalized at harvesting into DPLA Various native metadata fields mapped to dcterms:description 8

9 Problem statement Lack of systematic empirical studies of digital library metadata with the focus on free-text Description metadata in very large aggregations (e.g., Hathi Trust, Internet Archive, DPLA, etc.) 9

10 METHODS 10

11 Problem statement & Research Questions Lack of systematic empirical studies of digital library metadata with the focus on freetext Description metadata in very large aggregations (e.g., Hathi Trust, Internet Archive, DPLA, etc.) What is the overall usage of Description field by hubs in DPLA? How can length of data values provide insight into Description metadata practices among DPLA hubs? 11

12 Data collection & processing Big Data approach: DPLA Bulk Download over 11.5 million metadata records in a single compressed JSON file each record parsed, all instances of Description field extracted Solr full-text indexer for Description fields: Stats Component 12

13 Data analysis The findings presented here Level of application of Description field by DPLA hub field instances per record Length of data value in Description field range, mean, standard deviation of: number of characters number of words average word length proportion of data value that consist of letters, punctuation, or integers Content analysis of data values from Description field instances (n=200) 13

14 FINDINGS: LEVEL OF APPLICATION 14

15 % of records with 1+ Description instance Only 5 out of 29 hubs include Description in all records; 22 hubs include it in 50%+ of records 15

16 MAX number of Description instances per record 7 hubs with over 20 instances: 4 with over 50 undefined_provider the_portal_to_texas_history smithsonian 179 uiuc tn scdl nypl washington virginia usc nara mwdl missouri-hub artstor mdl kdl bhl cdl 65 david_rumsey digital-commonwealth digitalnc esdn georgia getty gpo harvard hathitrust indiana internet_archive 16

17 Average no. of Description instances per record Above 2.00 for 8 of 29 hubs: 5 of these hubs have unusually high max number of instances 17

18 % of Description instances with unique values 90.00% 80.00% 70.00% 60.00% 50.00% 40.00% 30.00% 20.00% 10.00% 0.00% Under 50% values are unique for all but 6 hubs 18

19 FINDINGS: LENGTH OF DATA VALUES 19

20 Ave. length of data values (no. of characters) 200 characters or less for most hubs Very high variability for 2 hubs 20

21 MAX length of data values (no. of characters) 21

22 More findings: content analysis of data values Data value in Description field Category 1 glass negative: b&w; 8 x 10 in.; sulfiding. Physical object description This material has been provided by The Royal College of Surgeons of England. Rights or usage The original may be consulted at The Royal College of Surgeons of England statement This image shows a section of Thorn Cemetery including gravestones. Microform. Title supplied by cataloger. This series contains transcripts of proceedings, depositions, and oral examinations prepared exclusively for or in the District Court. The depositions and oral examinations were taken out of court and are primarily interviews with School Board representatives and employees concerning the development, implementation, and review of desegregation plans. Object content description Object type or format Note or metadata source Collection-level content description Main source of non-unique data values (slide 18) P950. Identifier or call number 22

23 DISCUSSION, CONCLUSIONS & FUTURE RESEARCH 23

24 Variability issues Not all hubs (and/or partner institutions within service hubs) may: Unexpected: consider free-text Description fields (e.g., notes of various kinds) to be equally important, or enforce the usage of Description fields departure from best practice guidelines Wide variability of the number of instances of Description and the length of data values Higher (but not outlying) lengths could indicate more rigorous standards of Description in hubs Outlier records with Description field values 20,000 characters+ should be reviewed as to their appropriateness to local descriptive metadata input rules 24

25 Mapping issues The variety of information types observed in Description data values might be due to 1 or more factors: differing perceptions of Description semantics among DPLA hubs and contributors insufficient consistency of contributed records for more accurate mapping _ absence of a better match than Description to map the information from native metadata (richer than Dublin Core) in DPLA 25

26 Other possible problems Context Shorter values might be due to local practices where description of item is in the context of the description of collection Context lost in aggregation Quality Outliers with shortest data value lengths might indicate lack of relevant information about an item Outliers with longest data value lengths might be due to full text harvested with the metadata record 26

27 Conclusions Simple statistical analyses can provide better understanding of metadata usage in aggregation Large sets of empirical data (big data approach, eliminates sampling error) Diversity allows for better understanding of contributing institutions varying practices Recommendation for aggregators to include in metadata application profiles a separate Note property for mapping of information that does not fit Description Additional research is needed Some ideas on the next 2 slides 27

28 Future research Use of language in Description data values Data collected but not analyzed yet number of words average word length proportion of data values that consist of letters, punctuation, or integers proportion of words from list of frequently-used English works (e.g., 1K, 5K etc., standard English dictionary) 28

29 More future research Categorizing information in Description 1. automatically identifying some of this information to map data values more accurately or mark them for review for quality control Comparing perceived importance with actual application of Description metadata in DPLA hubs native metadata Research into: ü How different institutions perceive item-level (and collectionlevel) metadata in native systems and as part of an aggregation End-user perception of usefulness of descriptive information in helping find items could help to refine guidelines on Description field 29

30 Questions? Comments? Ideas? 30

31 Works cited Baca, M. and P. Harpring (Eds.). (2009) Categories for the Description of Works of Art (CDWA), Getty Research Institute, Santa Monica. Baca, M., et al. (2006) Cataloging Cultural Objects: A Guide to Describing Cultural Works and their Images, American Library Association, Chicago. Digital Public Library of America (2015a, March 5). An introduction to the DPLA metadata model. Retrieved from info/wp-content/uploads/2015/03/intro_to_dpla_metadata_model.pdf Digital Public Library of America (2015b, March 5). Metadata application profile: Version 4.0. Retrieved from Encoded Archival Description. (2002). Retrieved from Encoded Archival Description: EAD3. (2015). Retrieved from VersionEAD3.pdf. Jackson, A.S., M. Han, K. Groetsch., M. Mustafoff and T. W. Cole. (2008). Dublin Core metadata harvested through OAI-PMH. Journal of Library Metadata, 8(1), Hillmann, D. (2005). Using Dublin Core. Retrieved from Kurtz, M. (2010). Dublin Core, DSpace, and a brief analysis of three university repositories. Information Technology & Libraries, 29(1), Retrieved from OSU Knowledge Bank Metadata Application Profile for Digital Video. (2011). Retrieved from knowledge-bank/knowledgebankmetadataapplicationprofile2011.pdf Park, J. (2006). Semantic interoperability and metadata quality: An analysis of metadata item records of digital image collections. Knowledge Organization, 33 (1), Ward, J. (2003). A quantitative analysis if unqualified Dublin Core metadata element set usage within data providers registered with the Open Archives Initiative. Proceedings of the 2003 Joint Conference on Digital Libraries, pp Weagley, J., E. Gelches, & J. Park. (2010). Interoperability and metadata quality in digital video repositories: a study of Dublin Core. Journal of Library Metadata, 10(1), DOI: /