The 5 Star Open Data Standard developed by the Open Data Institute grades the openness of data:
| grade | Description | practical example and explanation |
| * | One star open data is accessible and it is open licensed (so people know they can re-use it); but it is in a form that makes it hard to process or re-use | A table of numbers in a PDF document format – you can read the numbers visually but you’ll probably end up having to re-enter the data to use it for another purpose. It’s better than nothing though. |
| ** | Two star open data is the same as above except that it is in a form that can be understood and processed by computer | A table of numbers in a proprietary spreadsheet format like Excel. To read XCL files you need to either have Microsoft Excel or a way of importing it to an application you can use to work on the data. When you need to re-use large amounts of data, having data in this form is much better than 1 star above. |
| *** | Three star open data is the same as above except that the form is generic – you don’t need a particular application to use it | An array of numbers in a generic format like CSV which you can import and use in a wide range of applications. (CSV is a very lightly structured way of making tables of figures). This is as open as data gets most of the time – though it’s often not much better in practical terms than 2 star above. |
| **** | Four star open data is the same as above except that it has it is referenced so that anyone can find it independently of knowing what document it might be published in | In technical terms this means that the set of data has its own URI (unique resource indicator – like a web address for example) which can be looked up by a person or by a computer application. Mostly this is just a nice-to-have but if you are using data dynamically (as it changes) it makes a massive difference. |
| ***** | Five star open data is the same as above except it is referenced internally and described so that anyone can find and use bits of it independently without knowing the document or structure it is in | The data set contains multiple URIs and has descriptors attached to each so that it can be used anywhere and re-applied in other uses equally easily. |
Now have a look at
the Open Data Institute website
OR – follow the menu on the right to have a look at other parts of the guide.