A behind-the-scenes blog about research methods at Pew Research Center. For our latest findings, visit pewresearch.org. Identifying causal relationships from observational data is not easy. Still, ...

Learn the steps and see examples of simple random sampling, which ensures each member of a population has an equal chance of ...

Make your R data.table code more efficient and elegant with these special symbols and operators. Plus, learn about the new fcase() function R data.table code becomes more efficient — and elegant — ...

For some data.table users, “dot-SD” is a bit of a mystery. But data.table creator Matt Dowle told me that it’s actually quite simple: Just think of it as a symbol representing “each group.” Let’s go ...