pster wrote:So, when Chicago doesn't have extra entries, is it because somebody looked at the text?
For the vast majority of word forms, no. These various tools use 'lemmatizers' — programs to parse each word in their corpus. If you were crazy enough to decide you wanted to run your own personal copy of the Perseus software, you would learn that one of the steps the install takes is for a program to go through every text
producing parsing information for each word and slamming it into a database (on old computers this can take days to run). By no means is this always accurate. Even the TLG lemmatizer
only gets about 95% of forms correct. I believe some of these tools have lengthy lists of exceptional forms to deal with oddities, but they probably omit a lot, too.
For a while there was a tool in Perseus which allowed people to vote on their choices when alternate forms presented themselves. I forget when that disappeared. I don't know how accurate people were in their judgements.