While powerful, Equation 5d does have limitations: - Assumptions: The model often assumes homogeneity within the population, ignoring variations in age, health status, and social behavior. - Data Quality: The accuracy of the model depends on the quality and timeliness of data. Incomplete or incorrect data can lead to inaccurate predictions. - Complexity: Real-world scenarios often involve multiple interacting factors that can be difficult to incorporate into a single equation.