Health Trajectory Analysis

A health score is a snapshot. A health trajectory is a motion picture. The trajectory — the direction and velocity of health score changes over time — is more predictive than the score itself. A customer with a score of 70 and a six-month declining trajectory is at higher risk than a customer with a score of 55 and a three-month improving trajectory. The first is heading toward trouble. The second is recovering from it. Trajectory analysis adds the time dimension that static scores cannot capture.

Trajectory analysis examines three properties of the health score movement. Direction: is the score rising, falling, or flat? Direction is the most basic trajectory signal. Velocity: how fast is the score changing? A slow decline over twelve months is a different risk profile than a rapid decline over three months — the rapid decline demands urgent intervention. Acceleration: is the rate of change itself changing? A score that has been declining slowly for six months and is now declining faster is exhibiting negative acceleration — the situation is deteriorating faster than before. Acceleration is the earliest warning signal because it detects the change in change.