8.3 Path types

• Front door path: all the arrows point away from Treatment

Front Door Paths

front door paths

• Back door path: at least one arrow pointing back toward Treatment

Back Door Paths

back door paths

• Good path: describes a reason why treatment and outcome are related that answers your research question

Good Paths

If the research question is “Does Wine cause Lifespan?”,

front door paths

• Bad path: describes a reason why treatment and outcome are related

  • unrelated to your research question
  • alternative explanation of the data

Bad Paths

If the research question is “*Other than how often it might affect drug-taking, does Wine cause Lifespan?“,

bad path

The key to identifying the answer to our research question, then, is to find a way to dig just the Good Paths out of the data without getting distracted by the Bad ones.