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Archive for the "Standards" Category

More of the same

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Categories: Announcements, Ideas, News, Standards

Posted 2 February 2016


Welcome to week one of the post-acquisition Rustici Software world. I just thought I’d take a moment here to discuss one of the reasons we agreed to sell Rustici Software to LTG, because it’s not all about the money.

Mike and I were seeking investment funding for Watershed, but we really weren’t on the lookout for anything related to Rustici Software. It was a profitable business, I know very well how to run it, and we have several sets of work that give us cause for optimism. LTG, however, saw the value in both Watershed from an investment point of view and Rustici Software from a market and profitability point of view.

After LTG’s first visit, Mike and I asked ourselves two questions.

  • Did we believe that we would be able to maintain our strange and highly-valued culture through an acquisition? Having a place we want to come to work has always been a fundamental requirement for us.
  • Did we believe that we would be able to serve our customers in the way we always had?

Throughout the negotiations, due diligence, and these two long days as an LTG company 😉 we’ve consistently believed that we could do both of those things and still do. LTG is not an LMS provider like some of our prior suitors have been. We always used to worry that an acquisition of that sort might include aggressive interactions with our customers. With LTG, we’re going to continue to be agnostic, supportive of the standards, and generally the same company we always have been. We’re excited about it, and excited about continuing to support our customers and the industry in general in exactly the same way.

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Statements come from all kinds of places: content created in authoring tools, mobile apps, learning platforms and business systems. It’s not always immediately obvious which application the statement came from, which might be useful to know. This blog explains how you can tag the statements your tool or product generates and why that information is useful.

We’ve worked hard to make the Tin Can (xAPI) spec as clear as possible and have required Learning Record Stores (LRSs) to validate incoming data to ensure the same data structure is always used. There’s no way for statements to be sent to a conformant LRS unless they follow the prescribed data structure, and you’ll find that the major LRSs are strict with the data they accept.

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We call it “I call it”

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Categories: Adopters, Announcements, APIs, Ideas, News, Standards,

Posted 20 August 2015



On August 13th, 2015, we launched a heavily revised version of Andrew Downes has been working away, as he does, creating new content. Rather than direct it all at the blog, though, he’s been rethinking and restructuring the core site and sharing his insights for first-timers, learning designers, learning product vendors, and organizations. There are countless other updates laid out below. Please spend some time with them.

Many readers of the site, though, will likely notice a significant change to our handling of the name… Years ago, Mike shared our perspective on the name, that we were going to call it Tin Can API. For some, this has been a contentious issue. With the new site, we’ve made the site behave as we have been personally for a long time. We call it whatever you call it.

On the site, you’ll notice a toggle in the upper left. If you prefer to call it Tin Can, do so. If you prefer xAPI, that’s great too. Whether you visit or, the site will present everything to you using your prefered name.

It comes down to this: arguing about an API’s name simply isn’t productive. We have far more important things to accomplish together.

So please, enjoy the new content. Go build a brilliant activity provider. Make some statements. Or ask us for help if you need it.



Here are the new sections of the site:


The existing Tin Can Explained page gives a really helpful introduction to Tin Can if you’ve never heard of it.  We’ve brought this section up to date a little and added some pages around the different components of the new enterprise learning ecosystem that Tin Can enables. We’ve also added pages targeted specifically at organizations, learning product vendors and vendors of products outside L&D.

Get Started

By now, if you haven’t heard of Tin Can and got a basic understanding, you’ve probably been living on mars. These days, the question we get asked most isn’t “what’s Tin Can?” but “how do I get started?” If that’s your question, then good news – we’ve created a new section just for you!

The get started section includes pages targeted at product vendors, content authors and organizations. It includes guides to help you see Tin Can in action, get a Learning Record Store (LRS) and run a pilot project in your organization. There’s a collection of pages to help you think about moving on from SCORM, too.


We already had a bunch of resources for developers, but not much really aimed at learning designers. We’ve added a page outlining the impact of Tin Can on learning design, including reflections on a handful of learning models and theories in the light of Tin Can. If you’re thinking more at the strategy level, we’ve got a page on incorporating Tin Can into your learning strategy, too.

At a practical level, there’s a guide on statement design, an introduction to recipes for learning designers, and an assignment for you to try out what you learn from the new pages we’ve written.


The developers section was already crammed full of resources. We’ve tidied these up to make them easier to find and created an interactive statement explorer page to help you understand the structure of the statement.

The statement generator we created a few years ago was due for an update and ADL recently published a new more comprehensive statement generator. We don’t believe in reinventing the wheel, so we’ve taken the ADL tool, made it orange and included it on the site.

To help you put all these resources into practice, we’ve created a series of challenges for developers to try out writing code for Tin Can.


The previous webinar list contained embedded YouTube videos for all our webinars. We’ve got so many webinar recordings now that it was getting hard to find webinars on specific topics so we’ve created a new categorized webinar list. Each of the webinars is now on its own page, making it easier to share the recording with other people.

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I’m super excited about the latest recipe we’ve published on the registry! Not only is it a great recipe tackling an important use case, but it was written by adopters who needed it for a real project. It was written incredibly rapidly, going from first draft to ready-to-try in less than two weeks. This blog gives you the details.

Sometimes when I talk to people about recipes, they’re disappointed to hear that there isn’t yet a recipe for the use case they are interested in. “Don’t worry!” I always console them, “You can write your own.” TES took that advice to heart and one of the first things they did after hiring a developer to take Tin Can further in their app was to draft up a recipe covering the events they wanted to track. In this case, attendance at events such as meetings, classroom sessions, conferences, etc.

The actual recipe can be found here in the registry. The recipe is split into ‘Simple Attendance’ which uses a single statement to record that a group attended the event, and ‘Detailed Attendance’ which is used to record more events such as scheduling, registering, joining and leaving. It’s envisaged that some recipe adopters will implement only Simple Attendance whilst others will compliment it with the nuances captured by Detailed Attendance statements.

The bulk of the recipe was written by Sean Donaghy of TES. I helped by reviewing each iteration and making a couple of edits where it was faster to make the change directly than write up an explanation. I’m very happy to help anybody who wants help with reviewing a recipe they’re working on.

This first release of the recipe is considered an alpha version. Aside from the TES developers who are busily implementing the recipe in their product, nobody else has tried the recipe yet. There are likely some changes to come as implementers run into challenges we couldn’t predict. If you do implement the recipe, we really appreciate your comments and feedback. You’ll use the recipe ids ( and as a “category” Context Activity so that when you upgrade to the final release version of the recipe you can easily identify which statements used which version.

Recipes are really important to ensure your statements can be understood by other tools. If you’re working on a Tin Can project and neither following nor writing a recipe, please do get in touch so I can help you.

You can expect this to be the Year of The Recipe for Tin Can. We already had the Open Badges recipe last month and there’s a few more in the works that will pop up as the year progresses. Watch this blog for more news sometime soon!

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Sharing Documents successfully

So far in this Deep Dive series on the Document API I’ve introduced you to the Document APIs in general and then looked in detail at each Document API in turn. In this final post of the series, we’ll explore two important complexities of the Document APIs that you need to pay particular attention to when multiple Activity Providers or users might be accessing the same Documents.

Sharing keys

As I mentioned in my State and Activity Profile API blog, there is no specific structure or naming convention for Document IDs in any of the Document APIs, but I recommend using IRIs to avoid conflict where two Activity Providers use the same key. This is especially important for the Agent Profile API where it’s more likely for Activity Providers to be accessing the same data. There’s also risk of two Activity Providers storing the same data in different places and missing an opportunity to share (e.g. DOB and dateOfBirth) or using different formats (“27/09/83” vs. “09/27/1983”) and conflicting with one another.

In order to avoid two Activity Providers storing the same data under different structures or using different formats, Communities of Practice will need to define their own Agent Profile Documents IDs and outline the structure and format of Documents they contain. Megan Bowe has done an excellent job of explaining the process of defining a profile within your own community of practice.

Once you’ve defined what data you’re going to store and how you’re going to store it, you should describe it in a Recipe in the Registry. A standard and unique Document ID should be used for each Agent Profile Document. This ensures that Activity Providers using the same Document ID follow the same structure. The Registry doesn’t currently have an area explicitly for registering Document API keys, but you can include them in Recipe descriptions. As Recipes are identified using Activity ids, some Recipes might even encourage APs to store some Documents in the State or Activity Profile APIs at the Recipe Activity id as a mechanism for sharing data between APs implementing that Recipe.

The scope of a community of practice that shares an Agent Profile might vary. A core recipe containing data such as gender might be shared by every Activity Provider implementing Tin Can. Other Recipes will be shared by a number of organizations with a shared interest. The draft CMI5 specification, for example, defines a learner preferences document including language and audio preference. Some Recipes may even be specific to a vendor or internal within an organization.

Many Activity Providers using the Agent Profile API will choose to implement multiple Recipes for Agent Profile data. An app and website for parachuting clubs, for example, will make use of gender data from a universal core Recipe, but could follow a parachuting specific Recipe for metrics such as number of jumps, parachute type preference, etc.

ETags and Concurrency

Another risk with multiple Activity Providers or Agents accessing the same Documents is that they could access the Documents at the same time and accidentally overwrite one another’s data. Imagine the following series of events relating to a Document that stores high scores for a mobile learning game:

  • The app on player one’s phone downloads the High Scores Document and inserts his score.
  • Meanwhile, player two completes a game and her phone downloads the High Scores Document and inserts her score
  • Player one’s phone stores the updated High Scores Document with his score.
  • Player two’s phone stores the High Scores Document unaware of the changes made by player one’s phone. His score is lost.

Tin Can makes use of ETags to prevent this happening. Every time a Document is updated, the LRS creates a new ETag for that Document, which it sends to the Activity Provider when they retrieve or store the Document. They then send the ETag back to the LRS when they make changes, telling the LRS which version of the Document they’re trying to modify. The LRS will reject any attempt to store a Document that doesn’t come with the latest ETag. ETags are simply a SHA1 hash of the document and are commonly used in applications across the internet; they’re not unique to Tin Can.

In the example above, when player two’s phone tried to store the updated High Scores Document, this would not actually overwrite player one’s score. Instead, the LRS would return an error to player two’s phone to let it know that the Document had changed. The app would then request the latest version of the Document from the LRS and get the latest ETag. It could then choose to try and merge its changes into the latest Document, drop its changes and keep the latest Document or overwrite the latest Document with its own version. You’ll need to choose which option works best in your application.

ETags are required for the Agent Profile and Activity Profile, but Activity Providers can choose whether or not to use them for the State API. I recommend using them anyway to avoid problems. The Tetris Prototype includes an example of using ETags with TinCanJS for the Activity Profile API.

You’ve seen in this post that sharing Documents between Activity Providers requires some effort to get right, but if done properly you should have no problems.

Now that you’ve reached the end of this blog series, you’re ready to start storing and retrieving Documents. All of our code libraries support interacting with the Document APIs. As always, please let us know if you have questions!

Go now, store Documents!

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