In this communication, the validity of experimental data reported in the literature for structure II and H hydrate dissociation conditions in the presence of water soluble/insoluble promoters are assessed. Outliers in the hydrate dissociation data are identified using a statistical method. The Leverage mathematical based approach is employed for determination of the statistical Hat matrix, sketching of the Williams plot, and computation of residual values (difference between calculated and experimental data) for a specific model. In addition, the range of applicability of the applied model and quality of the available experimental data is determined. Because of the high accuracy of the least squares support vector machine (LSSVM) method which has been used in previous studies, this method has been used for the prediction of dissociation conditions of clathrate hydrates of methane, carbon dioxide, nitrogen, and hydrogen in the presence of water soluble organic promoters (tetrahydrofuran (THF), 1,4-dioxane, and acetone) and twenty-one water insoluble hydrocarbon promoters. It is expected that the results reported in this study would provide a better understanding of the reliability of hydrate equilibrium data. This would enable the development of more accurate thermodynamic models based on reliable experimental data. (C) 2013 Elsevier B.V. All rights reserved.