Peter the skald wrote:
I do not see the need to roll secretly...could someone explain?
The most common need, IME, is for rolls relating to perception or awareness: in a lot of games, and with a lot of players, if you tell
them to roll a Spot/Notice/Perception/Awareness/Listen/whatever check, they're going to figure there's something to notice, and will act on it (even by just paying attention to someone). Context will often let them deduce what there was to notice anyway. If keeping a secret secret from them is important, rolling secretly may be necessary.
There's a few ways to counter this:
1. Keep track of the PCs' relevant skills, and roll secretly.
2. Bogus rolls: tell them to roll perception-type checks a lot, for no reason - pass or fail, you just go "mmhmm, mmhmm".
3. Undefined rolls, best combined with 2: "Roll. Hmmm. Okay... [play continues] "
4. Pre-rolls on a list. This was actually recommended in Cyberpunk 2020 for Notice checks, IIRC.
And probably others I'm not thinking of right now.
This is, obviously, a facet of a certain type of gaming - a specific idiom/paradigm. It's by no means necessary for all groups, playstyles, or games. As time goes on, more and more games move further from this essentially adversarial style to a cooperative style where keeping secrets from the players isn't as necessary.
I find it's perfectly possible to run a game where there are no secret rolls, especially if you dispose with a lot of rolling anyway. In a lot of situations, there's no reason for the PCs to notice things: this applies, for instance, in almost all Call of Cthulhu scenarios, where noticing things is mandatory for play to continue! (Something Trail of Cthulhu wonderfully fixes, I find.)
IMO the main importance of this kind of rolling is for ambushes and traps: if you don't use some kind of random roll, but spring the ambush/trap automatically, the players will (rightly) complain, because you've deprived them of agency very meaningfully, harming their characters. If you tell the players to roll such-and-such, they will usually contextually deduce the threat and react to it, even just a little.
The other is for noticing clues that are not obvious, but I think this one is fraught with danger. Like I indicate above, a lot of Call of Cthulhu scenarios hinge on this, and it is a bad idea
, because failure on a single roll can stop the entire story. Instead, I'd use it for "extra" clues: for instance, a PC is left alone in their employer's office, and the player does not state they are doing anything, so the DM makes a secret roll and, on success, informs the player that they notice a paper sticking out of a pile of papers that catches their eye, and on inspection, reveals that the employer is probably intending to double-cross them. (Secretly evil employers always write that stuff down!) If the player had been told to make a perception check, on a failure they might have decided to snoop around and would have reasonably discovered the paper anyway.
There's a lot of equally good approaches, of course, but that's just some reasonings.