Reflex Defense and Flat Footed???

Okay I have another noob question.  I have been reading the different source books SECR, Force Unleashed, and Legacy Era.  I have noticed that many characters have their reflex listed as well as another score for being flat footed.  How is this flat footed score calculated I have looked and cant seem to find it.  If I can get the page that would help.  Many thanks in advance.
It's very hard to find but it's on p 149 of the SECR.  Basically when your flat footed you loose your Dex Modifier and any dodge bonus (because they usually go when you can't use your Dex Mod).  There are other effects but those are the usual adjustments to Ref Def you see.
Alright thanks I appreciate the help.