This document discusses key concepts in empirical research for writing studies. It defines empirical research as systematic research with a plan and question, not just looking up information. Empirical research produces data that others can examine. The document also distinguishes between quantitative and qualitative research methods. Most writing research uses qualitative methods like interviews and observation rather than quantitative methods involving numbers. It notes that there are few experimental research designs in writing studies and that action research is similar to teacher research.