Enter the real world of data and statistics, and you find that files aren’t always neatly wrapped with a bow and delimited fields. Christopher Groskopf, who recently joined Quartz, provides an “exhaustive reference” to deal with the real stuff.
Most of these problems can be solved. Some of them can’t be solved and that means you should not use the data. Others can’t be solved, but with precautions you can continue using the data. In order to allow for these ambiguities, this guide is organized by who is best equipped to solve the problem: you, your source, an expert, etc. In the description of each problem you may also find suggestions for what to do if that person can’t help you.
The guide is aimed at journalists but easily applies to general data meanderings. I think we can all easily relate to problems such as missing data (“Where did the rest go?”), sample bias (“The population is who?”), and data in a difficult-to-manage format (“They gave you how many PDF files?”).
Bookmark it, read it, and keep it in your digital pocket.