How much format specific knowledge should a judge have to competently judge a comp-rel event of a certain format?
I realise that's a “how long is a piece of string” kind of question I'll try and narrow it down.

Tier-1 deck knowledge (the existence of what the most heavily played decks are and how the function)
Corner cases that are common to the format (the interaction of a set of cards specifically to the format)

Lack of understanding in the top case causes judges to give more GLs for Deck List Error than I think should be tolerable.
Lack of understanding in the second causes us to give incorrect rulings.

Should judges have to demonstrate good format knowledge before being given stewardship of such an event?

Does it matter the format?

I realise that often side events are given to advancing judges to help their advancement and large enough side events are required to help with that, but potentially these events should be better suited for HJs who have specific format knowledge.

Judges that believe they have the answer correct won't go digging for the correct answer unless pushed.

Should players expect format specific knowledge from Judges?
Should TOs expect format specific knowledge from Judges?

I don't care if a judge knows the metagame for a given format inside and
out, but I would like for them to understand the common but complex
interactions in that format, e.g. how split cards worked with
Counterbalance before Amonkhet.
If a judge lacks this knowledge, they should have resources at hand to help
sanity-check their rulings.
A judge given charge of such an event should know themselves well enough to
know what they don't know.

> On Sep 17, 2017, at 6:43 AM, Alex Gershaw <forum-38335-c9e6@apps.magicjudges.org> wrote:
>
> Lack of understanding in the top case causes judges to give more GLs for Deck List Error than I think should be tolerable.

I would argue that it's lack of the player writing full card names that causes players to earn game losses. If a player is sloppy with their list they are taking a risk.

While it's better to be very familiar with a format, it doesn't prevent the issue described, of giving incorrect rulings due to not knowing the answer. It's actually a judge's arrogance, that they're certain of an answer without confirming it first, that's the root cause of many incorrect rulings.

I feel that I can judge effectively in any format, including Eternal, because of two critical tools: first, a device hanging on my belt that gives me rapid access to Oracle text and Gatherer rulings; second, the self-awareness that I need to use the first.

I also agree with Bryan re: the real root cause of Decklist penalties; further, a judge's familiarity with a format should be a non-factor, as that handy device can quickly confirm which storyline characters exist in that format.

d:^D

I'd point out another area in which being familiar with a format helps: investigation. It helps to understand the strategic impact of a mistake if you know the deck's game plan, especially if you know what the match up is about, that if you don't.

But even if you don't, you have a great tool at hand: the player who committed the mistake. Asking about his or her game plan, and how that mistake interact with that game plan (while the opponent is away, of course!) is usually a great way to get information both about the strategy, but also about the player's behaviour and mindset.

- Emilien