I find myself in New York for the day on my way back from the excellent Smart Data 2015 Conference in San Jose. It’s a long story about red-eye flights and significant weekend savings which I won’t bore you with, but it did result in some great chill-out time in Central Park to reflect on the week.
In its long auspicious history the SemTech, Semantic Tech & Business, and now Smart Data Conference has always attracted a good cross section of the best and brightest in Semantic Web, Linked Data, Web, and associated worlds. This year was no different for me in my new role as an independent working with OCLC and at Google.
I was there on behalf of OCLC to review significant developments with Schema.org in general – now with 640 Types (Classes) & 988 properties – used on over 10 Million web sites. Plus the pioneering efforts OCLC are engaged with, publishing Schema.org data in volume from WorldCat.org and via APIs in their products. Check out my slides:
By mining the 300+ million records in WorldCat to identify, describe, and publish approx. 200 million Work entity descriptions, and [soon to be shared] 90+ million Person entity descriptions, this pioneering continues.
These are not only significant steps forward for the bibliographic sector, but a great example of a pattern to be followed by most sectors:
Identify the entities in your data
Describe them well using Schema.org
Publish embedded in html
Work with, do not try to replace, the domain specific vocabularies – Bibframe in the library world
Work with the community to extend an enhance Schema.org to enable better representation of your resources
If Schema.org is still not broad enough for you, build an extension to it that solves your problems whilst still maintaining the significant benefits of sharing using Schema.org – in the library world’s case this was BiblioGraph.net
Extending Schema.org Through OCLC and now Google I have been working with and around Schema.org since 2012. The presentation at Smart Data arrived at an opportune time to introduce and share some major developments with the vocabulary and the communities that surround it.
On a personal note the launch of these extensions, bib.schema.org in particular, is the culmination of a bit of a journey that started a couple of years ago with forming of the Schema Bib Extend W3C Community Group (SchemaBibEx) which had great success in proposing additions and changes to the core vocabulary.
A journey that then took in the formation of the BiblioGraph.net extension vocabulary which demonstrated both how to build a domain focused vocabulary on top of Schema.org as well as how the open source software, that powers the Schema.org site, could be forked for such an effort. These two laying the ground work for defining how hosted and external extensions will operate, and for SchemaBibex to be one of the first groups to propose a hosted extension.
Finally this last month working at Google with Dan Brickley on Schema.org, has been a bit of a blur as I brushed up my Python skills to turn the potential in version 2.0 in to the reality of fully integrated and operational extensions in version 2.1. And to get it all done in time to talk about at Smart Data was the icing on the cake.
Of course things are not stoping there. On the not too distant horizon are:
The final acceptance of bib.schema.org & auto.schema.org – currently they are in final review.
SchemaBibEx can now follow up this initial version of bib.schema.org with items from its backlog.
New extension proposals are already in the works such as: health.schema.org, archives.schema.org, fibo.schema.org.
More work on the software to improve the navigation and helpfulness of the site for those looking to understand and adopt Schema.org and/or the extensions.
The checking of the capability for the software to host external extensions without too much effort.
And of course the continuing list of proposals and fixes for the core vocabulary and the site itself.
I believe we are on the cusp of a significant step forward for Schema.org as it becomes ubiquitous across the web; more organisations, encouraged by extensions, prepare to publish their data; and the SEO community recognise proof of it actually working – but more of that in the next post.
The Culture Grid closed to ‘new accessions’ (ie. new collections of metadata) on the 30th April
The existing index and API will continue to operate in order to ensure legacy support
Museums, galleries, libraries and archives wishing to contribute material to Europeana can still do so via the ‘dark aggregator’, which the Collections Trust will continue to fund
Interested parties are invited to investigate using the Europeana Connection Kit to automate the batch-submission of records into Europeana
The reasons he gave for the ending of this aggregation service are enlightening for all engaged with or thinking about data aggregation in the library, museum, and archives sectors.
Throughout its history, the Culture Grid has been tough going. Looking back over the past 7 years, I think there are 3 primary and connected reasons for this:
The value proposition for aggregation doesn’t stack up in terms that appeal to museums, libraries and archives. The investment of time and effort required to participate in platforms like the Culture Grid isn’t matched by an equal return on that investment in terms of profile, audience, visits or political benefit. Why would you spend 4 days tidying up your collections information so that you can give it to someone else to put on their website? Where’s the kudos, increased visitor numbers or financial return?
Museum data (and to a lesser extent library and archive data) is non-standard, largely unstructured and dependent on complex relations. In the 7 years of running the Culture Grid, we have yet to find a single museum whose data conforms to its own published standard, with the result that every single data source has required a minimum of 3-5 days and frequently much longer to prepare for aggregation. This has been particularly salutary in that it comes after 17 years of the SPECTRUM standard providing, in theory at least, a rich common data standard for museums;
Metadata is incidental. After many years of pump-priming applications which seek to make use of museum metadata it is increasingly clear that metadata is the salt and pepper on the table, not the main meal. It serves a variety of use cases, but none of them is ‘proper’ as a cultural experience in its own right. The most ‘real’ value proposition for metadata is in powering additional services like related search & context-rich browsing.
The first of these two issues represent a fundamental challenge for anyone aiming to promote aggregation. Countering them requires a huge upfront investment in user support and promotion, quality control, training and standards development.
The 3rd is the killer though – countering these investment challenges would be possible if doing so were to lead directly to rich end-user experiences. But they don’t. Instead, you have to spend a huge amount of time, effort and money to deliver something which the vast majority of users essentially regard as background texture.
As an old friend of mine would depressingly say – Makes you feel like packing up your tent and going home!
Interestingly earlier in the post Nick give us an insight into the purpose of Culture Grid:
.… we created the Culture Grid with the aim of opening up digital collections for discovery and use ….
That basic purpose is still very valid for both physical and digital collections of all types. The what [helping people find, discover, view and use cultural resources] is as valid as it has ever been. It is the how [aggregating metadata and building shared discovery interfaces and landing pages for it] that has been too difficult to justify continuing in Culture Grid’s case.
In my recent presentations to library audiences I have been asking a simple question “Why do we catalogue?” Sometimes immediately, sometimes after some embarrassed shuffling of feet, I inevitably get the answer “So we can find stuff!“. In libraries, archives, and museums helping people finding the stuff we have is core to what we do – all the other things we do are a little pointless if people can’t find, or even be aware of, what we have.
If you are hoping your resources will be found they have to be referenced where people are looking. Where are they looking?
It is exceedingly likely they are not looking in your aggregated discovery interface, or your local library, archive or museum interface either. Take a look at this chart detailing the discovery starting point for college students and others. Starting in a search engine is up in the high eighty percents, with things like library web sites and other targeted sources only just making it over the 1% hurdle to get on the chart. We have known about this for some time – the chart comes from an OCLC Report ‘College Students’ Perceptions of Libraries and Information Resources‘ published in 2005. I would love to see a similar report from recent times, it would have to include elements such as Siri, Cortana, and other discovery tools built-in to our mobile devices which of course are powered by the search engines. Makes me wonder how few cultural heritage specific sources would actually make that 1% cut today.
Our potential users are in the search engines in one way or another, however it is the vast majority case that our [cultural heritage] resources are not there for them to discover.
Culture Grid, I would suggest, is probably not the only organisation, with an ‘aggregate for discovery’ reason for their existence, that may be struggling to stay relevant, or even in existence.
You may well ask about OCLC, with it’s iconic WorldCat.org discovery interface. It is a bit simplistic say that it’s 320 million plus bibliographic records are in WorldCat only for people to search and discover through the worldcat.org user interface. Those records also underpin many of the services, such as cooperative cataloguing, record supply, inter library loan, and general library back office tasks, etc. that OCLC members and partners benefit from. Also for many years WorldCat has been at the heart of syndication partnerships supplying data to prominent organisations, including Google, that help them reference resources within WorldCat.org which in turn, via find in a library capability, lead to clicks onwards to individual libraries. [Declaration: OCLC is the company name on my current salary check] Nevertheless, even though WorldCat has a broad spectrum of objectives, it is not totally immune from the influences that are troubling the likes of Culture Graph. In fact they are one of the web trends that have been driving the Linked Data and Schema.org efforts from the WorldCat team, but more of that later.
How do we get our resources visible in the search engines then? By telling the search engines what we [individual organisations] have. We do that by sharing a relevant view of our metadata about our resources, not necessarily all of it, in a form that the search engines can easily consume. Basically this means sharing data embeded in your web pages, marked up using the Schema.org vocabulary. To see how this works, we need look no further than the rest of the web – commerce, news, entertainment etc. There are already millions of organisations, measured by domains, that share structured data in their web pages using the Schema.org vocabulary with the search engines. This data is being used to direct users with more confidence directly to a site, and is contributing to the global web of data.
There used to be a time that people complained in the commercial world of always ending up being directed to shopping [aggregation] sites instead of directly to where they could buy the TV or washing machine they were looking for. Today you are far more likely to be given some options in the search engine that link you directly to the retailer. I believe is symptomatic of the disintermediation of the aggregators by individual syndication of metadata from those retailers.
Can these lessons be carried through to the cultural heritage sector – of course they can. This is where there might be a bit of light at the end of the tunnel for those behind the aggregations such as Culture Grid. Not for the continuation as an aggregation/discovery site, but as a facilitator for the individual contributors. This stuff, when you first get into it, is not simple and many organisations do not have the time and resources to understand how to share Schema.org data about their resources with the web. The technology itself is comparatively simple, in web terms, it is the transition and implementation that many may need help with.
Schema.org is not the perfect solution to describing resources, it is not designed to be. It is there to describe them sufficiently to be found on the web. Nevertheless it is also being evolved by community groups to enhance it capabilities. Through my work with the Schema Bib Extend W3C Community Group, enhancements to Schema.org to enable better description of bibliographic resources, have been successfully proposed and adopted. This work is continuing towards a bibliographic extension – bib.schema.org. There is obvious potential for other communities to help evolve and extend Schema to better represent their particular resources – archives for example. I would be happy to talk with others who want insights into how they may do this for their benefit.
Schema.org is not a replacement for our rich common data standards such as MARC for libraries, and SPECTRUM for museums as Nick describes. Those serve purposes beyond sharing information with the wider world, and should be continued to be used for those purposes whilst relevant. However we can not expect the rest of the world to get its head around our internal vocabularies and formats in order to point people at our resources. It needs to be a compromise. We can continue to use what is relevant in our own sectors whilst sharing Schema.org data so that our resources can be discovered and then explored further.
So to return to the question I posed – Is There Still a Case for Cultural Heritage Data Aggregation? – If the aggregation is purely for the purpose of supporting discovery, I think the answer is a simple no. If it has broader purpose, such as for WorldCat, it is not as clear cut.
I do believe nevertheless that many of the people behind the aggregations are in the ideal place to help facilitate the eventual goal of making cultural heritage resources easily discoverable. With some creative thinking, adoption of ‘web’ techniques, technologies and approaches to provide facilitation services, reviewing what their real goals are [which may not include running a search interface]. I believe we are moving into an era where shared authoritative sources of easily consumable data could make our resources more visible than we previously could have hoped.
Are there any black clouds on this hopeful horizon? Yes there is one. In the shape of traditional cultural heritage technology conservatism. The tendency to assume that our vocabulary or ontology is the only way to describe our resources, coupled with a reticence to be seen to engage with the commercial discovery world, could still hold back the potential.
As an individual library, archive, or museum scratching your head about how to get your resources visible in Google and not having the in-house ability to react; try talking within the communities around and behind the aggregation services you already know. They all should be learning and a problem shared is more easily solved. None of this is rocket science, but trying something new is often better as a group.
About a month ago Version 2.0 of the Schema.org vocabulary hit the streets.
This update includes loads of tweaks, additions and fixes that can be found in the release information. The automotive folks have got new vocabulary for describing Cars including useful properties such as numberofAirbags, fuelEfficiency, and knownVehicleDamages. New property mainEntityOfPage (and its inverse, mainEntity) provide the ability to tell the search engine crawlers which thing a web page is really about. With new type ScreeningEvent to support movie/video screenings, and a gtin12 property for Product, amongst others there is much useful stuff in there.
But does this warrant the version number clicking over from 1.xx to 2.0?
These new types and properties are only the tip of the 2.0 iceberg. There is a heck of a lot of other stuff going on in this release that apart from these additions. Some of it in the vocabulary itself, some of it in the potential, documentation, supporting software, and organisational processes around it.
Sticking with the vocabulary for the moment, there has been a bit of cleanup around property names. As the vocabulary has grown organically since its release in 2011, inconsistencies and conflicts between different proposals have been introduced. So part of the 2.0 effort has included some rationalisation. For instance the Code type is being superseded by SoftwareSourceCode – the term code has many different meanings many of which have nothing to do with software; surface has been superseded by artworkSurface and area is being superseded by serviceArea, for similar reasons. Check out the release information for full details. If you are using any of the superseded terms there is no need to panic as the original terms are still valid but with updated descriptions to indicate that they have been superseded. However you are encouraged to moved towards the updated terminology as convenient. The question of what is in which version brings me to an enhancement to the supporting documentation. Starting with Version 2.0 there will be published a snapshot view of the full vocabulary – here is http://schema.org/version/2.0. So if you want to refer to a term at a particular version you now can.
How often is Schema being used? – is a question often asked. A new feature has been introduced to give you some indication. Checkout the description of one of the newly introduced properties mainEntityOfPage and you will see the following: ‘Usage: Fewer than 10 domains‘. Unsurprisingly for a newly introduced property, there is virtually no usage of it yet. If you look at the description for the type this term is used with, CreativeWork, you will see ‘Usage: Between 250,000 and 500,000 domains‘. Not a direct answer to the question, but a good and useful indication of the popularity of particular term across the web.
This refers to the introduction of the functionality, on the Schema.org site, to host extensions to the core vocabulary. The motivation for this new approach to extending is explained thus:
Schema.org provides a core, basic vocabulary for describing the kind of entities the most common web applications need. There is often a need for more specialized and/or deeper vocabularies, that build upon the core. The extension mechanisms facilitate the creation of such additional vocabularies.
With most extensions, we expect that some small frequently used set of terms will be in core schema.org, with a long tail of more specialized terms in the extension.
As yet there are no extensions published. However, there are some on the way.
As Chair of the Schema Bib Extend W3C Community Group I have been closely involved with a proposal by the group for an initial bibliographic extension (bib.schema.org) to Schema.org. The proposal includes new Types for Chapter, Collection, Agent, Atlas, Newspaper & Thesis, CreativeWork properties to describe the relationship between translations, plus types & properties to describe comics. I am also following the proposal’s progress through the system – a bit of a learning exercise for everyone. Hopefully I can share the news in the none too distant future that bib will be one of the first released extensions.
W3C Community Group for Schema.org A subtle change in the way the vocabulary, it’s proposals, extensions and direction can be followed and contributed to has also taken place. The creation of the Schema.org Community Group has now provided an open forum for this.
So is 2.0 a bit of a milestone? Yes taking all things together I believe it is. I get the feeling that Schema.org is maturing into the kind of vocabulary supported by a professional community that will add confidence to those using it and recommending that others should.
Schema.org is basically a simple vocabulary for describing stuff, on the web. Embed it in your html and the search engines will pick it up as they crawl, and add it to their structured data knowledge graphs. They even give you three formats to chose from — Microdata, RDFa, and JSON-LD — when doing the embedding. I’m assuming, for this post, that the benefits of being part of the Knowledge Graphs that underpin so called Semantic Search, and hopefully triggering some Rich Snippet enhanced results display as a side benefit, are self evident.
The vocabulary itself is comparatively easy to apply once you get your head around it — find the appropriate Type (Person, CreativeWork, Place, Organization, etc.) for the thing you are describing, check out the properties in the documentation and code up the ones you have values for. Ideally provide a URI (URL in Schema.org) for a property that references another thing, but if you don’t have one a simple string will do.
There are a few strangenesses, that hit you when you first delve into using the vocabulary. For example, there is no problem in describing something that is of multiple types — a LocalBussiness is both an Organisation and a Place. This post is about another unusual, but very useful, aspect of the vocabulary — the Role type.
At first look at the documentation, Role looks like a very simple type with a handful of properties. On closer inspection, however, it doesn’t seem to fit in with the rest of the vocabulary. That is because it is capable of fitting almost anywhere. Anywhere there is a relationship between one type and another, that is. It is a special case type that allows a relationship, say between a Person and an Organization, to be given extra attributes. Some might term this as a form of annotation.
So what need is this satisfying you may ask. It must be a significant need to cause the creation of a special case in the vocabulary. Let me walk through a case, that is used in a Schema.org Blog post, to explain a need scenario and how Role satisfies that need.
Starting With American Football
Say you are describing members of an American Football Team. Firstly you would describe the team using the SportsOrganization type, giving it a name, sport, etc. Using RDFa:
So we now have Chucker Roberts described as an athlete on the Touchline Gods team. The obvious question then is how do we describe the position he plays in the team. We could have extended the SportsOrganization type with a property for every position, but scaling that across every position for every team sport type would have soon ended up with far more properties than would have been sensible, and beyond the maintenance scope of a generic vocabulary such as Schema.org.
This is where Role comes in handy. Regardless of the range defined for any property in Schema.org, it is acceptable to provide a Role as a value. The convention then is to use a property with the same property name, that the Role is a value for, to then remake the connection to the referenced thing (in this case the Person). In simple terms we have have just inserted a Role type between the original two descriptions.
This indirection has not added much you might initially think, but Role has some properties of its own (startDate, endDate, roleName) that can help us qualify the relationship between the SportsOrganization and the athlete (Person). For the field of organizations there is a subtype of Role (OrganizationRole) which allows the relationship to be qualified slightly more.
So far I have just been stepping through the example provided in the Schema.org blog post on this. Let’s take a look at an example from another domain – the one I spend my life immersed in – libraries.
There are many relationships between creative works that libraries curate and describe (books, articles, theses, manuscripts, etc.) and people & organisations that are not covered adequately by the properties available (author, illustrator, contributor, publisher, character, etc.) in CreativeWork and its subtypes. By using Role, in the same way as in the sports example above, we have the flexibility to describe what is needed.
Take a book (How to be Orange: an alternative Dutch assimilation course) authored by Gregory Scott Shapiro, that has a preface written by Floor de Goede. As there is no writerOfPreface property we can use, the best we could do is to is to put Floor de Goede in as a contributor. However by using Role can qualify the contribution role that he played to be that of the writer of preface.
<span property="roleName"src="http://id.loc.gov/vocabulary/relators/wpr">Writer of preface</span>
<span property="contributor"src="http://http://viaf.org/viaf/283191359">Floor de Goede</span>
You will note in this example I have made use of URLs, to external resources – VIAF for defining the Persons and the Library of Congress relator codes – instead of defining them myself as strings. I have also linked the book to it’s Work definition so that someone exploring the data can discover other editions of the same work.
Do I always use Role? In the above example I relate a book to two people, the author and the writer of preface. I could have linked to the author via another role with the roleName being ‘Author’ or <http://id.loc.gov/vocabulary/relators/aut>. Although possible, it is not a recommended approach. Wherever possible use the properties defined for a type. This is what data consumers such as search engines are going to be initially looking for.
One last example
To demonstrate the flexibility of using the Role type here is the markup that shows a small diversion in my early career:
@prefix schema:<http://schema.org/> .
This demonstrates the ability of Role to be used to provide added information about most relationships between entities, in this case the employee relationship. Often Role itself is sufficient, with the ability for the vocabulary to be extended with subtypes of Role to provide further use-case specific properties added.
Whenever possible use URLs for roleName In the above example, it is exceedingly unlikely that there is a citeable definition on the web, I could link to for the roleName. So it is perfectly acceptable to just use the string “Keyboards Roadie”. However to help the search engines understand unambiguously what role you are describing, it is always better to use a URL. If you can’t find one, for example in the Library of Congress Relater Codes, or in Wikidata, consider creating one yourself in Wikipedia or Wikidata for others to share. Another spin-off benefit for using URIs (URLs) is that they are language independent, regardless of the language of the labels in the data the URI always means the same thing. Sources like Wikidata often have names and descriptions for things defined in multiple languages, which can be useful in itself.
Final advice This very flexible mechanism has many potential uses when describing your resources in Schema.org. There is always a danger in over using useful techniques such as this. Be sure that there is not already a way within Schema, or worth proposing to those that look after the vocabulary, before using it.
Good luck in your role in describing your resources and the relationships between them using Schema.org