The reaction rates from these calculations can be compared to estimates from the detailed isobutanol mechanism by Sarathy et al. Two other isobutanol mechanisms, published by Hui et al. and Merchant et al. , do not include explicit representation of peroxy radicals, so these cannot be compared directly to the calculations here. The Sarathy mechanism uses pressure-independent rate coefficients, which were compared to our high-pressure-limit rate coefficients. Of our 38 reactions, only 25 correspond directly to reactions in the Sarathy mechanism. The Waddington mechanism, which the Sarathy mechanism represents as one step, was also added and is compared to the βAlkoxyIsom reaction in this work. These reactions were compared at 50 temperatures between 500 and 1000 K. At each temperature, a ratio was taken of the rate in this work to rates in the Sarathy mechanism, and the mean of the ratios at the 50 temperatures is designated as the deviation between the two models. Figure shows the deviation for the 25 reactions as a histogram, with color coding indicating different types of reactions.