These articles cover the fundamentals: data, techniques, statistics, etc.
Visualization Research, Part I: Engineering
Conventions in visualization can seem arbitrary, and quite a few are. But there is also a vast body of research, and it is growing every day. Just how does visualization research work? How do we learn new things about visualization and how it can and should be used?
Putting Data Into Context
Raw numbers are easy to report and analyze, but without the proper context, they can be misleading. Is the effect you’re seeing real, or a simple result of the underlying, obvious distribution? Too many analyses and news stories end up reporting things we already know.
What Means Mean
Data is often reported as a single number. Unemployment rates, housing prices, crime, etc. are all boiled down to single numbers that average over a large population. But averages, or means, hide much of the richness of the underlying data, and without at least a sense of the spread of the data values, are largely meaningless.