Over several months, Will, Daniela, and the team painstakingly poured over 27.5 million documents, previously leaked through the Panama Papers, Paradise Papers, and more, to reveal how the region’s elites hide billions offshore. Here’s what they had to say.

What you asked

With such a large volume of data to work through, you asked: how did you determine a starting point for the analysis?

Will: "Data is never the be all and end all. One misconception some people -- even reporters -- still have is that leaked documents tell a complete story. That’s rarely true and certain isn’t true with any of these offshore leaks. So the starting point of West Africa Leaks was explaining and understanding the offshore system. We had to ask questions like:

• 'Why would someone want to use a Panama shell company?'
• 'What does it mean if the person uses a nominee shareholder?'
• 'What laws, if any, in Mali, Senegal, Niger or Liberia require citizens or politicians to declare financial assets?'

We needed to ask the big questions first before diving in. Otherwise, you’re going in blind and likely to get the wrong end of the stick."

Daniela: "Companies or individuals will often set up offshore structures following the same patterns. With Will in the room, we managed to analyse such patterns and those that had led to successful investigations before. For example, he instructed reporters to “check if the person you are investigating had to declare financial assets according to his/her position in X organisation”. With such advice, the journalist could benefit from the knowledge built up already."

Right, so then how did you corroborate and verify the stories that were published?

Will: "After years of reporting on these documents, we have strong confidence in them. But still, every leaked document must be corroborated and verified. So, for example, if the address of a politician was given at a certain street and city in a country, for example, we would use open records (if available) or existing media reporting to confirm that address. We also used online government registries, where available, to confirm the incorporation date of certain offshore companies.

The real takeaway is this: leaked documents are your friends, but make sure you know who your friends are before trusting them completely."

From a technical point of view, what was the biggest challenge?

Daniela: "We tried to tackle all possible complications at the moment we met in Senegal. From encryption and security of communication to searching the documents (some even in Spanish language!) everything was covered when we met. However, how can you search a database that needs three encryption methods if you have three power cuts within two hours? You can’t download the files, you have to reload every time, re-login, re-start the search and so on. It is not impossible but it is hard. That is the reality many of our journalists faced. And yet they managed to succeed."

And the tools you used?

Will: "We’re talking about millions of PDFs, emails, image files, invoices, bank statements and spreadsheets. Some go back to the 1980s and even 1970s! ICIJ has a crack team of data experts who used technologies like Apache Tika (to extract metadata and text), Apache Solr (to build search engines) and others (you can read more about it here -- I’m not one of these data geniuses!).

ICIJ’s data team built open source software called Extract that helps make documents machine-readable and searchable. That’s key -- this was how we could search for words like “Monrovia” or “Ouagadougou” and get results. We then use user-friendly web portals, such as Blacklight for the Panama Papers, to which all participating journalists receive secure logins via encrypted email.

We also use -- and provide to partners -- programs such as the Linkurious database and Neo4j, a technology that allows data to be converted into much more human-friendly graph form."

What’s next? Are there plans to extend the investigation to the rest of Africa?

Will: "Yes! ICIJ and CENOZO have plans to make sure that all of West Africa is covered. If there is anything that we have learned from major data leaks it is that the more, the merrier. Sometimes it takes that one journalist with knowledge about a certain piece of a puzzle to be able to find what hundreds of other reporters missed. ICIJ is also very keen to develop more and deeper partnerships with journalists in Eastern Africa."

Is your question missing? To read Will and Daniela’s full Q&A, click here.

Our next conversation

For our next edition, we thought we’d get visual -- we're going to hear all about your favourite type of chart and why.

Until next time,

Madolyn from the EJC Data team