Duane plot for Parametric Growth Curve

The Duane plot is a scatterplot of the cumulative failure rate versus time. Use a Duane plot to do the following:
  • Assess whether your data follow a power-law process or a homogeneous Poisson process.
  • Determine whether your system is improving, deteriorating, or remaining stable.

The fitted line on the Duane plot is the best fitted line when the assumption of the power-law process is valid and the shape and scale are estimated using the least squares method.

The Duane plot should be approximately linear if the power-law process or homogeneous Poisson process is appropriate. A negative slope shows reliability improvement, a positive slope shows reliability deterioration, and no slope (a horizontal line) shows a stable system.

Example output


For the air conditioning data, an outlier appears at approximately 20 days. The data approximately follow a horizontal line, which indicates that the power-law process is an adequate model and that the system is relatively stable.

By using this site you agree to the use of cookies for analytics and personalized content.  Read our policy