[phoenixmj]

We use OGUST when partner opens 2 of a suit. Any new suit bid over a 2 level preempt is considered 1 round force.

How about a 3 level preempt by partner? Is a bid of a new suit forcing? Is there any system in place to evaluate the strength of opener's hand and/or suit?

Thanks in advance.

[Stephen Tu]

New suit that isn't game is forcing, with std agreements. There isn't really any system to find out how strong opener is because if you move you are basically already in game.
For slam purposes, there are a fair number of people who use 4c (over non club preempt) as a modified keycard ask (search internet for "preempt keycard").
Also sometimes jumps in suits can be used as control asks (so to bid 4H over 3c, to play, you have to bid 3H followed by 4H; direct 4H is an asking bid for control in hearts.) This is decidedly non-std so don't try it without discussion.

[steve2005]

3♦ over 3♣ to ask for a 3-card major can be useful.