Reliability growth – a new graphical model

A new reliability growth model is presented which is simpler to plot and fits the data more closely than the Duane model over the range of Duane slopes normally observed during a reliability growth programme. The model is derived from variance stabilization transformation theory. The problem, inherent in Duane's model, of providing too much influence to earlier failures is overcome. A method is also presented of comparing different models which have different y-axes. Extensive simulations were conducted and the results indicate that for Duane slopes less than 0.5 the new model is more effective. The leverage and influence aspects of both models are evaluated by means of Cook's distance. Finally, two published datasets are analysed and the findings confirm the simulation results.