Causal Inference 101

5 min read

Treatment, outcome, and confounders

The core variables in any causal study — defined clearly with examples from medicine, marketing, and policy.

Every causal analysis starts by naming three roles: treatment (the intervention), outcome (what you measure), and confounders (variables that influence both treatment and outcome).

Treatment can be binary (received email yes/no), continuous (dose level), or categorical (program type). Outcome can be continuous (revenue), binary (converted), or time-to-event (survival).

Confounders in practice

In medicine, age and baseline severity often confound drug assignment and health outcomes. In marketing, prior engagement confounds who receives a promotion and who purchases. In policy, regional wealth confounds program rollout and employment.

Including the right confounders in your analysis is not optional — it is how you justify a causal claim in observational data.

What to list before you analyze

  • Treatment: exactly what changed and for whom?
  • Outcome: measured when and how?
  • Confounders: what influenced both treatment assignment and outcome?
  • Instruments or time structure: is DiD or IV plausible?

Run this method on your data — no Python

CausalLens runs matching, DiD, causal forests, DoWhy refutation, and more — with balance tables, sensitivity checks, and PDF export.