I haven't compiled or studied the numbers that would allow me to offer an analysis on the issue. Such a study would be interesting, but would also be quite problematic, not to mention controversial, in regard to methodology. With regular troops, you can sit down with a pen, paper, reports and calculator and come up with a number. Such numbers would not likely vary in a significant way from researcher to researcher.

As for irregulars, in regard to methodology a researcher would first have to define who exactly was an irregular (a complicated issue that was rife with controversy back in 1864, let alone 2011), and then scour through anecdotal material to try to come up with numbers (which, at best, would be guesswork). You would also have to come up with a definition as to what counted as a kill. Killed in battle? Or taken out of their homes and killed while in custody (which was a prominent aspect of irregular warfare)?

In addition, a regular soldier was a regular soldier. You look at his records and either he was one or he wasn't. Conversely, a man could be an irregular one day, and give it up the next. At what point is he no longer an irregular? Kill him today in the field, he's an irregular, find him at home with his wife and kids tomorrow and kill him is he still an irregular? One day, and he no longer is one? Or does it take a week of peaceful activity before he is no longer an irregular? Or a month, or a year?

Federals killed many a man called guerrilla or bushwhacker or partisan or what have you, simply because they were suspected of bad acts. How many men like that died who was called a guerrilla but may have only had the wrong attitude toward Union authority?

I would be interested in hearing from others in regard to this issue (including possible methodology in conducting such a study)--we'll have to take care and try to base our posts less on philosophy and more on tangible sources, otherwise I can see the matter getting kicked over to the News and Views site in a hurry.