Notes on WHEREBY

From Wiktionary:

Use of whereby as a formal equivalent of where is nonstandard and is avoided by careful speakers and writers, who use where or in which instead. The term typically fails readability and comprehension review so it is generally avoided in published works. The term is also avoided by speakers as it makes it difficult to understand the message that is trying to be communicated.

http://en.wiktionary.org/wiki/whereby