The HyChem (hybrid chemistry) approach has been proposed recently for modeling high-temperature combustion of real, multicomponent fuels. The approach combines lumped reaction steps for fuel thermal and oxidative pyrolysis with detailed chemistry for oxidation of the resulting pyrolysis products. The 14 independent model parameters in the lumped reaction steps are determined by matching the time histories of key pyrolysis products of the fuel, obtained notably from the Stanford shock tube and laser diagnostics facilities, and from flow reactor experiments. The prediction accuracy of HyChem model depends on the availability of the speciation data and their accuracy. In the present work, we carry out comprehensive Monte Carlo analysis of model predictions with respect to species measurement using the Jet A HyChem model as the test case. We assess the impact of the measured fuel pyrolysis products, including ethylene (C2H4), methane (CH4), propene (C3H6), iso-butene (i-C4H8), 1-butene (1-C4H8), benzene (C6H6), and toluene (C7H8) on HyChem predictions using ignition delay time and laminar flame speed as test cases. The results show that the speciation data are necessary to obtain reliable predictions for the laminar flame speed and ignition delay time at and above 1200 K. Additional measurement targets (e.g., CO and CH2O) are proposed for future HyChem model development, especially in improving model predictions for ignition delay time. (C) 2020 The Combustion Institute. Published by Elsevier Inc. All rights reserved.