Scientific Method and Sources

The LifeTrajectory life-expectancy calculation builds on two core foundations: the Living to 100 Life Expectancy Calculator and the published BMC Medicine study by Li, Liu, Liao and colleagues. LifeTrajectory adapts these foundations into a transparent educational estimate and personalized feedback.

Core Calculation Foundations

• Living to 100 Life Expectancy Calculator
  A research-based tool derived from centenarian studies and a core foundation for the LifeTrajectory calculation.
  View the Original Calculator
• Li, K., Liu, C., Liao, L. et al.
  Lifestyle risk factors and residual life expectancy at age 40
  BMC Medicine (2014)
  Read the Full Article

How LifeTrajectory Uses These Foundations

• The questionnaire organizes personal inputs across major lifestyle, health-measurement, and family-history areas.
• The calculation adapts the core foundations above into a consistent educational estimate.
• The Feedback Map shows which answers influenced the estimate instead of presenting only a final number.
• The AI Action Plans are a guidance layer built on the completed result; they are not the source of the life-expectancy calculation.

Research Context and Further Reading

• Professor Thomas T. Perls, MD, MPH and the New England Centenarian Study
  Research context on the genetic and lifestyle factors associated with exceptional longevity.
  View the Study Overview
• Lifespan: Why We Age – and Why We Don't Have To, David A. Sinclair
  Further conceptual reading on aging biology. This book is not a core input to the LifeTrajectory life-expectancy calculation.