From: Olympia, WA
Certain aspects about intel are always reliable, some are vague, and some are subject to manipulation by a cagey enemy. I don't think there's anything you can do to make it more reliable, but with experience you'll become more adept at reading it.
Here are some examples:
1. Always reliable (as far as I know): (a) There are xxx troops at yyy; (b) XXX Unit is aboard YYY Maru bound for Port ZZZ; XXX Unit is prepping for YYY Base.
2. Vague: Major radio transmissions at hex xx/yy. It's hard to know whether that's the KB, a combat TF, or a delusion.
3. Subject to manipulation: See Item 1(b) above, that is supposedly always reliable? Well, a cagey player can load a unit aboard a Maru, set the target as some distant and deceiving port, and then unload at a waypoint somewhere else. Cagey, cagey, and difficult to unravel, but great fun.
Anybody can read SigInt and get good information from it, but with experience you'll get better at using it and using against your opponent. It's a really fun part of the game, at least if you're the Allied player.
BTW Dan, our mutual opponent is good at playing those games. fair warning...