The value of public data increases when it is in use. Opening data reserves is surprisingly easy.

1Choose the data you want to publish

Start with the data that you know is most in demand. In the best case, you will end up making your own work easier.

Is the database already in a format that can be published? Publish it first. Do you get requests for the same Excel sheet time after time? Publish the raw data of the table online and advise those who request it to compose their own statistics. You can also list your most important data reserves and ask the application developers what they feel is the most interesting one.

Alternative, you can follow the money: what is the most expensive information for you to collect and maintain? It is likely to be valuable for others as well. Only by giving it a trial run will you know what inspires the utilisers of data.

For instance the numerical data of Helsinki’s traffic accidents published as open data on HRI’s website ended up as impressive visualisations on the websites of national media such as Helsingin Sanomat, Suomen Kuvalehti and MTV3.

2Get your licence sorted

In order for your data to be put to reuse, the user needs to have legal rights to use it. The broadest possible license encourages the use of the data.

Most public administration data is public on the grounds of the freedom of information legislation. You should still check whether property rights restrict redistribution of the data and whether releasing the data would violate information privacy. In the terms of use, you can choose the international Creative Commons licences or the model licence of the HRI project. Making the terms of use clear and conformant to standards means less work for both the publisher and the users of the data.

The Helsinki Region Environmental Services Authority HSY, for example, chose the HRI licence when it published information on land reserves as open data. To assure data protection, the data on the property level was anonymised to district level.

3Publish online

Publish your data in machine-readable form. HTML and PDF files are easy for humans to read but computers appreciate XML.

For the users, the most important thing is that the data is available in an open format that computer software can process. There is no need to be fancy with your first data release: just save the content of your database in a comma-delimited file and upload it on your website together with the description of the content. You can later build more sophisticated interfaces on the basis of the user feedback.

The collection data of the Helsinki Metropolitan Area libraries, for instance, was initially published as a two-gigabyte raw file. Later on, the publisher built an interface which enables one to make searches directly from the library database.

4 Gather feedback, discuss

Register your data release on the data catalogue managed by HRI. Follow the feedback given to your dataset on Facebook or Twitter. Gather feedback in user meetings or in application competitions such as Apps4Finland. With the help of the feedback, your next data release will be an even greater success.

For instance, Helsinki Region Transport organised a competition to speed up the unlocking of public transport data. The competition looked for the best mobile applications making use of the data. It achieved considerable popularity: more than 60 mobile applications were submitted..