Our biggest mistake was thinking it’d be easy.

In late 2009, long before the nuclear accident in Japan, I had embarked on an investigative series on nuclear power. Under the direction of Associated Press National Investigative Editor Rick Pienciak, I was examining how well nuclear power plants hold up as they age. I was focusing on considering harmful factors within the plants, everything from radiation to rust. Soon, I began to wonder about safety outside the plants’ grounds. Had population growth in surrounding communities undermined what was once viewed as a fundamental safety feature of the plants: remote locations ...

Somewhere in the tilting tower of boxes that passes for my personal archive are the files from my first attempt at data journalism—an investigative piece about the Minneapolis Police Department’s Sex Crimes Unit. You’ll find no CDs with database files in there. No printed spreadsheets either; just a small stack of hand-drawn grids with case counts, closure stats, and other vitals. I don’t even know if I had Microsoft Excel installed on my work computer at the time. It never occurred to me that there might be a better way to store and process the information ...