Datadive Reproducibility – Time for a DataBox?

Whilst at the Global Witness “Beneficial Ownership” datadive a couple of weeks ago, one of the things I was pondering  – how to make the weekend’s discoveries reproducible on the one hand, useful as a set of still working legacy tooling on the other – blended into another: how to provide an on-ramp for folk attending the event who were not familiar with the data or the way in which t was provided.

Event facilitators DataKind worked in advance with Global Witness to produce an orientation exercise based around a sample dataset. Several other prepped datasets were also made available via USB memory sticks distributed as required to the three different working groups.

The orientation exercise was framed as a series of questions applied to a core dataset, a denormalised flat 250MB or so CSV file containing just over a million or so rows, with headers. (I think Excel could cope with this – not sure if that was by design or happy accident.)

For data wranglers expert at working with raw datafiles and their own computers, this doesn’t present much of a problem. My gut reaction was to open the datafile into a pandas dataframe in a Jupyter notebook and twiddle with it there; but as pandas holds dataframes in memory, this may not be the best approach, particularly if you have multiple large dataframes open at the same time. As previously mentioned, I think the data also fit into Excel okay.

Another approach after previewing the data, even if just by looking at it on the command line with a head command, was to load the data into a database and look at it from there.

This immediately begs several questions of course  – if I have a database set up on my machine and import the database without thinking about it, how can someone else recreate that? If I don’t have a database on my machine (so I need to install one and get it running) and/or I don’t then know how to get data into the database, I’m no better off. (It may well be that there are great analysts who know how to work with data stored in databases but don’t know how to do the data engineering stuff of getting the database up and running and populated with data in the first place.)

My preferred solution for this at the moment is to see whether Docker containers can help. And in this case, I think they can. I’d already had a couple of quick plays looking at getting the Companies House significant ownership data into various databases (Mongo, neo4j) and used a recipe that linked a database container with a Jupyter notebook server that I could write my analysis scripts in (linking RStudio rather than Jupyter notebooks is just as straightforward).

Using those patterns, it was easy enough to create a similar recipe to link a Postgres database container to a Jupyter notebook server. The next step – loading the data in. Now it just so happens that in the days before the datadive, I’d been putting together some revised notebooks for an OU course on data management and analysis that dealt with quick ways of loading data into a Postgres data, so I wondered whether those notes provided enough scaffolding to help me load the sample core data into a database: a) even if I was new to working with databases, and b) in a reproducible way. The short answer was “yes”. Putting the two steps together, the results can be found here: Getting started – Database Loader Notebook.

With the data in a reproducibly shareable and “live” queryable form, I put together a notebook that worked through the orientation exercises. Along the way, I found a new-to-me HTML5/d3js package for displaying small  interactive network diagrams, visjs2jupyter. My attempt at the orientation exercises can be found here: Orientation Activities.

Whilst I am all in favour of experts datawranglers using their own recipes, tools and methods for working with the data – that’s part of the point of these expert datadives – I think there may also be mileage in providing a base install where the data is in some sort of immediately queryable form, such as in a minimal, even if not properly normalised, database. This means that datasets too large to be manipulated in memory or loaded into Excel can be worked with immediately. It also means that orientation materials can be produced that pose interesting questions that can be used to get a quick overview of the data, or tutorial materials produced that show how to work with off-the-shelf powertool combinations (Jupyter notebooks / Python/pandas / PostgreSQL, for example, or RStudio /R /PostgreSQL ).

Providing a base set up to start from also acts as an invitation to extend that environment in a reproducible way over the course of the datadive. (When working on your own computer with your own tooling, it can be way too easy to forget what packages (apt-get, pip and so on) you have pre-installed that will cause breaking changes to any outcome code you show with others who do not have the same environment. Creating a fresh environment for the datadive, and documenting what you add to it, can help with that, but testing in a linked container, but otherwise isolated, context really helps you keep track of what you needed to add to make things work!

If you also keep track of what you needed to do handle undeclared file encodings, weird separator characters, or password protected zip files from the provided files, it means that others should be able to work with the files in a reliable way…

(Just a note on that point for datadive organisers – metadata about file encodings, unusual zip formats, weird separator encodings etc is a useful thing to share, rather than have to painfully discover….)

Using tools like Docker is one way of improving the shareability of immediately queryable data, but is there an even quick way? One thing I want to explore on my to do list is the idea of a “databox”, a Raspberry Pi image that when booted runs a database server and Jupyter notebook (or RStudio) environment. The database can be pre-seeded with data for the datadive, so all that should be required is for an individual to plug the Raspberry Pi into their computer with an ethernet cable, and run from there. (This won’t work for really large datasets – the Raspberry Pi lacks grunt – but it’s enough to get you started.)

Note that these approaches scale out to other domains, such as data journalism projects (each project on its own Raspberry PI SD card or docker-compose setup…)

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