Odds of Succesful Stealth

[nittanytbone14]

A thief, in a "typical" dungeon crawl, needs to hide & move silently in order to get into position for an ambush and backstab.

He is allowed to attempt it, at a movement penalty, with a -5 penalty to the roll.

Assuming DEX prime, a +2 DEX modifier, and a +2 bonus from something else (buffs, magic items, racial advantages, etc) our rogue has a 70% of passing each check before penalties. Let's assume it is a level appropriate foe for now, which cancels out the rogue's added level.

Now factor in a -5 penalty and the odds are only 45%.

45% x 45% = 20.25%

Thus our hapless rogue succeeds in setting up for a backstab only 1/5 of the time. If he must make a new pair of rolls each round he needs to move silently & hide to get into position, the odds drop even more rapidly.

Is this harsher than any other application of the SIEGE engine/skill system? Not only does it require two checks but it also is twice as hard to get bonuses (two different checks) and a -5 penalty is applied to boot.

It just seems quite punishing, especially compared to other editions (AD&D or 3.5).

[serleran]

Except, under most (ideal) circumstances, the rogue actually makes his check against a zero difficulty, and if he succeeds, usually prevents the opponent from getting a check at all... so, the proposition is skewed due to improper application. And, you're forgetting that an AD&D thief cannot move and hide at the same time, and the 3rd edition rogue takes a larger penalty (as I recall) but they tend to have more bonuses so its rather moot to compare anything to a d20 anything - the only times the odds really matter are at level 1 and at that level the C&C character cannot move and hide simultaneously.

So, really, this is not a comparable analysis.

[Harry Joy]

It doesn't require two checks. It takes a successful Move Silently OR Hide. And, you didn't add the Rogue's level to the check. He would get that.

And that's Back Attack. Sneak Attack does not require a Hide or Move Silently check. Only that the target is "unaware".

[Treebore]

Contrary to the movies it isn't easy to sneak up on someone who is truly "on guard".

So the CK needs to decide if the target is actually on alert or a sloppy and lazy guard, or a "common" person walking down a street, etc...

If they are not alert then the thief adds their level, but there is no CL modifier. So the thief would add their level and not have it offset.

So this is a situation where a CK, and the player, really need to put some thought into the situational modifiers.

Plus you are also assuming "level appropriate" means equal to the thieves level. I define it as "appropriate challenge level", which means to me that I have the opponent be of a level to give you a fair challenge.

So you may be fifth level, but I will likely have the guard as first or second level. Giving you a 3 or 4 point advantage on top of the base line chances.

Thats how I look at it anyways.
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[nittanytbone14]

serleran wrote:
Except, under most (ideal) circumstances, the rogue actually makes his check against a zero difficulty

Would not one add t he HD of the victim/observer as a Challenge Class?

That would in theory cancel out the bonus gained from the rogue's level, assuming a "level appropriate" foe.

[serleran]

Quote:
Would not one add t he HD of the victim/observer as a Challenge Class?

Only if one should. You do not get level / HD simply because its there. If the CK decides there is no chance for the perceiver to notice, there is no check. This happens a lot - ie, lazy aloof guards having a conversation near a roaring flame, drowned further by the clink of their metal boots vs the stealthy thief approaching very slowly in soft leather boots.

The CK must adjudicate when a NPC gets to check. Stealth tends to work both ways: its for the party when they use it, and its against them when they go lax. Leave your guard down, you get smacked... universal law.

[CharlieRock]

I would allow for one check (either hide or move silently). If the rogue is silent who is going to look at him, and if they are hiding they have already met the criteria for backstabbing someone.

I would also not allow the victim/opponent to make a counter check unless the rogue failed in the first place. If both fail the rogue is still pretty much undetected (such as when you accidently scare someone in your own home).
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The Rock says ...

Know your roll!

[vegabond]

OK, now after rereading the entries for Hide and Move Silently I'm confused.

I calculate a Dex prime 1st level rogue with +2 Dex and +2 racial bonus will succeed at a HIDE check against a normal guard 65% of the time. Only needing a 7 to pass. (ok here)

I calculate a Dex prime 3rd level rogue with +2 Dex, +2 racial bonus and -5 move penalty (because he wants to move too) will succeed at a HIDE check against a normal guard 50% of the time. Needing a 10 to pass. (uh what)

If the 1st level makes it, she can move up to 1/2 normal speed and remain hidden (no movement check needed unless she moves faster). Ooooooo...k.

If the 3rd level makes it, he can move up to 1/4 normal speed and has to make a Move silently check at -5. hmmmm that doesn't seem right.

How can a Hide check allow a 1st level rogue to move 1/2 speed, but a 3rd level rogue has to make a Hide & Move silently check at -5 EACH and can only move at 1/4 speed?

I guess I don't understand how a rogue can move and remain hidden and DOES NOT have to make a move silently check.

If she is hidden and moves does the guard then get to make a listen check? Is that the deal?

Also isn't this an attribute check? But level isn't added to this check? Where does it say that in the book?

And why don't you add the opponents level as the CL? Are we just making up rules as we go or what?

[serleran]

The problem is the rules are jumbled all over the place and they are seemingly contradicted - this is because each ability references the other. There is a special case exception for "stealth" found in hide - this ruling applies only while trying to hide and move silently simultaneously. All other times the abilities work exactly as written - that is, moving silently on its own works as written, as does hide when its used separately.

Quote:
How can a Hide check allow a 1st level rogue to move 1/2 speed, but a 3rd level rogue has to make a Hide & Move silently check at -5 EACH and can only move at 1/4 speed?

No. The 1st level rogue cannot move and hide at the same time. That ability is earned at level 3, as quoted in the PHB 3rd print, page 15:

"Rogues cannot hide and move silently at the same time until they reach 3rd level."

So, the reference to 1/2 movement and the -5 penalty applies only to those of 3rd+ level, not to those of 1-2nd since they can't do it at all. The only exception is the "move to cover" for the hide ability which is a -10 penalty.

A 3rd level rogue can move faster than half speed but takes a greater penalty to the check (up to -20, if running or charging.)

If a rogue attempts the "stealth" option of moving silently and hiding at the same time, that is an automatic -5 penalty - doing this means the character moves at 1/4 speed: if they want to go faster, they have to take the -5 penalty to get to half, and more if they want to go full... that means, technically, moving half speed while hiding is a -10 overall penalty.

Quote:
I guess I don't understand how a rogue can move and remain hidden and DOES NOT have to make a move silently check.

They do, page 15, PHB 3rd print: "At this level and beyond, a rogue can attempt both but must make a successful conceal [this should read hide] and move silent check at -5."

Quote:
If she is hidden and moves does the guard then get to make a listen check?

Depends. A rogue that moves silently does so with absolute silence. Unless the Castle Keeper feels there is a save allowed, there is none. But, being silent does not mean unseen, and being unseen does not mean being silent - this is a situational ability and must be adjudicated as it happens and cannot be universally ruled. Remember, it works against the party, too.

Quote:
Also isn't this an attribute check?

Yes, its a Dexterity check, twice.

Quote:
But level isn't added to this check?

Level is added; but, the OP said that level would be canceled out by the difficulty, which is the same thing as not adding it. This is the part that may, or may not, be true as mentioned above.

Quote:
And why don't you add the opponents level as the CL?

The opponent might not warrant it. It might be, or might not be, used. That depends on what the opponent is doing... and if the CK says they get level/HD.

Quote:
Are we just making up rules as we go or what?

No, just adjudicating the rules as they are written for situations as they arise.

Oh, and by the way - this is how I read what is there. If the "1/4" was changed to "1/2" a lot of this issue would drop away. But, if you did that, you'd lose a neat little pattern: ie, the double-double of speed reduction : penalty as shown below--

1/4 speed = -5

1/2 speed (double 1/4) = -10

full speed (double 1/2) = -20

[vegabond]

OK, well that is how I was originally reading it, but having the 3rd level bit at the beginning of the 3rd paragraph in Hide makes things "jumbled" as you say.

So a 1st-2nd level rogue can Hide or duck for cover.

A 3rd and higher level rogue can Hide and Move Silently but at a -5 to both while moving 1/4 speed. Got it.

Thanks for clearing that up.