Make Data Available (Technical Openness)

Open data needs to be technically open as well as legally open. Specifically, the data needs to be available in bulk in a machine-readable format.

Data should be priced at no more than a reasonable cost of reproduction, preferably as a free download from the Internet. This pricing model is achieved because your agency should not undertake any cost when it provides data for use.
In bulk
The data should be available as a complete set. If you have a register which is collected under statute, the entire register should be available for download. A web API or similar service may also be very useful, but they are not a substitutes for bulk access.
In an open, machine-readable format
Re-use of data held by the public sector should not be subject to patent restrictions. More importantly, making sure that you are providing machine-readable formats allows for greatest re-use. To illustrate this, consider statistics published as PDF documents, often used for high quality printing. While these statistics can be read by humans, they are very hard for a computer to use. This greatly limits the ability for others to reuse that data.

Here are a few policies that will be of great benefit:

  • Keep it simple,
  • Move fast
  • Be pragmatic.

In particular it is better to give out raw data now than perfect data in six months’ time.

There are many different ways to make data available to others. The most natural in the Internet age is online publication. There are many variations to this model. At its most basic, agencies make their data available via their websites and a central catalogue directs visitors to the appropriate source. However, there are alternatives.

When connectivity is limited or the size of the data extremely large, distribution via other formats can be warranted. This section will also discuss alternatives, which can act to keep prices very low.

Online methods

Via your existing website

The system which will be most familiar to your web content team is to provide files for download from webpages. Just as you currently provide access to discussion documents, data files are perfectly happy to be made available this way.

One difficulty with this approach is that it is very difficult for an outsider to discover where to find updated information. This option places some burden on the people creating tools with your data.

Via 3rd party sites

Many repositories have become hubs of data in particular fields. For example, is designed to connect people with sensors to those who wish to access data from them. Sites like and allow public sector agencies to store massive quantities of data for free.

Third party sites can be very useful. The main reason for this is that they have already pooled together a community of interested people and other sets of data. When your data is part of these platforms, a type of positive compound interest is created.

Wholesale data platforms already provide the infrastructure which can support the demand. They often provide analytics and usage information. For public sector agencies, they are generally free.

These platforms can have two costs. The first is independence. Your agency needs to be able to yield control to others. This is often politically, legally or operationally difficult. The second cost may be openness. Ensure that your data platform is agnostic about who can access it. Software developers and scientists use many operating sytems, from smart phones to supercomputers. They should all be able to access the data.

Via FTP servers

A less fashionable method for providing access to files is via the File Transfer Protocol (FTP). This may be suitable if your audience is technical, such as software developers and scientists. The FTP system works in place of HTTP, but is specifically designed to support file transfers.

FTP has fallen out of favour. Rather than providing a website, looking through an FTP server is much like looking through folders on a computer. Therefore, even though it is fit for purpose, there is far less capacity for web development firms to charge for customisation.

As torrents

BitTorrent is a system which has become familiar to policy makers because of its association with copyright infringement. BitTorrent uses files called torrents, which work by splitting the cost of distributing files between all of the people accessing those files. Instead of servers becoming overloaded, the supply increases with the demand increases. This is the reason that this system is so successful for sharing movies. It is a wonderfully efficient way to distribute very large volumes of data.

As an API

Data can be published via an Application Programming Interface (API). These interfaces have become very popular. They allow programmers to select specific portions of the data, rather than providing all of the data in bulk as a large file. APIs are typically connected to a database which is being updated in real-time. This means that making information available via an API can ensure that it is up to date.

Publishing raw data in bulk should be the primary concern of all open data intiatives. There are a number of costs to providing an API:

  1. The price. They require much more development and maintainence than providing files.
  2. The expectations. In order to foster a community of users behind the system, it is important to provide certainty. When things go wrong, you will be expected to incur the costs of fixing them.

Access to bulk data ensures that:

  1. there is no dependency on the original provider of the data, meaning that if a restructure or budget cycle changes the situation, the data are still available.
  2. anyone else can obtain a copy and redistribute it. This reduces the cost of distribution away from the source agency and means that there is no single point of failure.
  3. others can develop their own services using the data, because they have certainty that the data will not be taken away from them.

Providing data in bulk allows others to use the data beyond its original purposes. For example, it allows it to be converted into a new format, linked with other resources, or versioned and archived in multiple places. While the latest version of the data may be made available via an API, raw data should be made available in bulk at regular intervals.

For example, the Eurostat statistical service has a bulk download facility offering over 4000 data files. It is updated twice a day, offers data in Tab-separated values (TSV) format, and includes documentation about the download facility as well as about the data files.

Another example is the District of Columbia OCTO’s Data Catalogue, which allows data to be downloaded in CSV and XLS format in addition to live feeds of the data.