Introduction to propensity scores

A propensity score is crucial in observational studies that are designed to estimate the effect of treatments, interventions, or exposures. They function by calculating the probability of a unit, such as a person, receiving a specific treatment based on their observable characteristics. This methodology serves the vital purpose of creating a balanced comparison group, essential for causal inference in observational studies. By doing so, propensity scores help to emulate the conditions of a randomized controlled trial (RCT). These trials are the gold standard in experimental design but are often not feasible or ethical in every research scenario.

Imagine a large-scale multiplayer video game where players can choose to join one of two factions: the Rebels or the Empire. Each player has various attributes, such as skill level, experience points, preferred weapons, and playtime. In an ideal world (like an RCT), players would be randomly assigned to...