Statistical analysis of bug discovery data is used in the software industry to check the quality of the testing process and estimate the reliability of the tested program. In this paper, we show that the same techniques are applicable to hardware design veri cation. We performed a study on two implementations of state-of-the-art PowerPC processors that shows that these techniques can provide quality information on the progress of veri cation and good predictions of the number of bugs left in the design and the future MTTF.