Which are the Best Properties to Use

the only firm conclusions that can be drawn from these various investigations of different descriptor types is that combinations can be good and that the choice of descriptor, including the selection of subsets and possible combinations, is a vital part of the overall model building process. 

Summary of discriminant analysis results for a set of 90 mutagens (reproduced with permission from reference 75). 

ID Analysis Pooled data sef No. of variables Classification function (% correct) Jackknifed validation (% correct) 

Another problem with the choice of descriptors is accessibility. Some types of proprietary parameters are only available through the licensing of commercial software. There are, however, some web-based resources, such as Chembench (http //chembench.mml.unc.edu) and the Virtual Computational Chemistry Laboratory (www.vcclab.org) which both provide not only descriptor calculation facilities, but also access to statistical analysis routines. The molecular descriptors website (www.moleculardescriptors.eu) and QSAR world websites (www.qsarworld.com/qsar-web-based-programs.php) also provide useful links to resources such as databases and programs. 

We have come a long way since the earliest use of quantitative descriptions of chemical structure using experimental measurements such as solubility, boiling 

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