With online and digital tools, however, the field has been opened up to all.
"There's so much more data available out there," said Robyn Tomlin, chief digital officer at the Pew Research Center, speaking at the International Newsroom Summit in Amsterdam today.
"And new tools make [data journalism] so much easier to do."
There are four main phases to telling a story with data, she said, each with a rising level of value to the public.
"The process of 'data, filter, visualise and story' is how you do data journalism," she said, and just as there is more data available, the tools to manipulate it are becoming more widespread as well.
Tomlin shared some "free and easy" tools that will help journalists tell their stories at every stage of the process.
Gather the data
You can't do data journalism without data, but where can you find datasets to work with?
Datacatalogs.org is an extensive resource of datasets, maintained by data experts from around the world.
There are currently 390 catalogs available on the site, provided by users, covering countries, states, regions, international institutions and non-government organisations.
Some organisations or governments can try to "hide" data in PDFs as data is very difficult to extract from that particular file format, said Tomlin.
Thankfully, the free, open-source tool Tabula will scan a PDF and pull out the data "in seconds", she said, and is regularly used by The Times, ProPublica, Foreign Policy and other respected journalism outlets.
Clean the data
Cleaning or filtering the data to find the story is the second stage in the process, Tomlin said.
Datawrangler and OpenRefine are both free tools made available to help journalists clean up data.
They may seem complicated to use at first, but Tomlin stressed that she is not a developer or technically-minded and quickly got to grips with the tools thanks to a range of online video tutorials.
Video tutorial of DataWrangler
Organise and analyse data
Overview is a "great way to find and analyse data", Tomlin said, because it allows the user to search through massive volumes of text to find trends and themes.
"You could take the Wikileaks data and it would allow you to find particular words," she said, "find words that appear often so you can find themes, look for associations between words, all without having to read thousands of pages."
Google, too, is "your friend when it comes to data journalism", said Tomlin. Google spreadsheets are an easy, free way to organise and collaborate on data sets and Fusion tables can help to map and analyse that data.
Datawrapper lets users copy and paste their data into the back end, or upload it in a number of different file formats, before choosing from a selection of different formats to visualise the data.
Similarly, Infogram offers 30 different formats of graphics to present data with, and is a free service with some extra features unlocked if you choose to pay.
"Data tools are about storytelling and that's what we do as journalists," she said. "These are ways to help you tell new forms of stories."
- Getting started in data journalism: the first steps in a story
- How to: data journalism on a budget
- 'Data+Design': free ebook released for data visualisation
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