So apparently according to the following response by Ross Watson on this page http://www.fantasyflightgames.com/edge_foros_discusion.asp?efpag=6&efid=179&efcid=3&efidt=381609 the degrees of success from the defender cancel out those of the attacker. This is the first time I hear of such a rule in either DH, RT or DW, and looking through the books in Opposed Tests and Degrees of Success sections, I can find nothing resembling this rule. Can anyone point me to any mention of this rule in any of DH/RT/DW products, especially seeing how this changes the effectiveness of the Librarian and Force Weapons (on the channeling Opposed test)?

This was the original question and answer by the way:

6) When an Opposed Skill test is made, do the degrees of success of the loser negate any degrees of success of the winner? i.e. A Librarian is using his Force Weapon’s special ability and makes a focus power test (with 4 degrees of success) vs opposed WP test of the victim (with 1 degree of success). Does the Librarian have 4 d.o.s. or only 3 d.o.s.?

Yes, in an Opposed Test, degrees of success from the defender cancel out those of the attacker. In the example given, the Librarian would have succeeded at the Opposed Test with three degrees of success.

In my games I also add the degree of failure of the defender to the degree of success of the attacker, But I don't know if it is RAW, it just logical from my point of view.

My question is that this seems to be the very first time in RAW that degrees of success of defender subtract from degrees of success of the attacker in Opposed tests. I've also combed through errata for DH and RT and I can find no other mention of this rule. Is this something new to Deathwatch now? Or am I totally missing the page this rule's supposed to be on?

It's something new to Deathwatch because I have only seen the Deathwatch book and yes it is somewhere in there. I remember reading it somewhere in the skills or the combat section but I cannot provide a page reference, sorry.

Dodge is effectively an opposed test to BS v Fully or Sem-Auto Fire.
p238 under Dodge: "...When Dodging Full Auto or Semi-Auto Bursts, each degree of success on the Dodge Test negates one additional hit."

This would be an example of an opposed test of a similar nature to the opposed willpower test for a Force Weapon's extra damage.

Warhawk X said:

I SWEAR I've read this somewhere in the book as well, but for the life of me I can't find it

I'll keep looking.

Seems to make sense to me.

Not keen on the degree of failure adding to the winner's success, though. Missing a parry is easy to do, but it would take a spectacular failure to ensure that your foe hits you more/better because of that parry. One could easily end up in a situation where it's not worth trying to oppose a test, because it's likely to result in a worse loss than trying.

Another example: Arm wrestling. One looses without trying and the foe gets 3 successes. Now with a bit of effort and some dice rolled, the character can easily be beaten 'more' by actually trying.

In short, I might add 1 level of success if the looser fumbled the roll, but would never generally consider adding the margin of failure to the winner's successes.

@Siranui

I wasn't aware parry was an opposed test. I thought it was a success test for the attack, followed by a success test for the parry.

Of course I may be wrong, don't have my book with me...

EDIT: My point being though that I think that there would be few, if any, opposed tests that would be better to just fail rather than roll (and possibly fail), because of this mechanic. Or at least, opposed checks the character would have a choice to participate in (as I imagine a force weapon doesn't give you the option to not make the opposed willpower test).

Parry was a bad example. I was thinking outside of the game system there. [However, isn't a disarm an opposed test?]

I just don't like to further penalise people for trying, basically.