Simple to test for yourself. Just clash twice the same armies when boosting only your attack (alternatively only your defense) and go as the atttacker once and as the defender the other time.

This is a forum, it's meant to ask and answer questions. 

There are too many variables to take into account to test all of the attributes and some players don't have the time to spend for testing everything. How do I know if I need to spend time and resources by carrying out offensive studies if I intend to play deffensive by now? How can I find out what to study if there's nowhere we can find that information? Obviously I need the info before I spend my resources and time, so the "test by myself" stuff is a catch-22. Or do you suggest I study offensive skills to find out if it works in defense or not? 

This is a forum. If you are not willful to help and answer questions maybe you shouldn't be here.

hai

hai

Well health is calculated in all equasions wether your attacking or defending so always good. Same with enemy health reduction. Im not positive on attack or defense boosts/reductions.

yea often wondered this myself. When you attack someone, is your defense value useless since your attacking. Is it ONLY calculating your attack value vs their defense value, and same with defending. If someone attacks your city, does it take into account your attack value at all since your the one being attacked, or is defense the only factor in that equasion (along with your health of course).