This document discusses ex post facto research, which investigates causes and effects after they have been manifested. It describes two approaches - starting with subjects differing on an independent variable or dependent variable. Key points include characteristics like examining causes retrospectively, advantages like exploring relationships when experiments aren't possible, and disadvantages like inability to prove causation. The stages of an ex post facto investigation are outlined, including defining the problem, hypotheses, data collection methods, and analysis. Controls in this type of research include matching groups and accounting for extraneous variables.