[solvarn]

In 4E how do you go about gauging what an appropriate challenge is for players? What baseline do you use to create Grunts and Prime Runners? Are there certain formulae or point allocations used?

[Zilfer]

This probably isn't the answer your looking for but I often judge on the fly, per the occasion of the test. Now i know quite often this can give some DM's a power rush when they want NPC's to succeed but I try to be reasonable thinking well this guy is a guard just hired to keep an eye out. His gun is mostly for show but he knows how to use it should he need it. So i assign him a Dice pool of like 6. <.< which you'd be amazed the amount of hits i get with six dice.

I roll in front of my group without a screen so they do not like my guys. They'll roll 10+ dice sometimes up to 20 dice and i'll foil their shot with a lot of successes.

<.< this one zombie not different from any of the others except being lucky as hell, kept rolling 4 successes on 6 dice to dodge bullets that would put him down. He lasted a 2 full combat turns with 3 initiative passes? xD This was of course before i knew that additional shots lower your reaction pool.

Anyways it also helps to know what your group can handle damage wise, though there still should be a threat of death to them. I try to gauge how the players are doing on the run, are they being particularly smart? how trained are the opposition, and any other things that might come into account.

Hope that helped in at least some small way, if not forgive me. Sumimasen.... <.<

[Critias]

Take a look at some character sheets (or just wing it by memory), and look at what kind of dice they're generally rolling to attack, to dodge, and to soak damage.  Gauge from there;  you want them to (generally) be fighting a larger group (so you'll generally want "easy" NPCs to attack with a couple less dice than they're dodging with, to factor in multiple attack penalties), and...well, just take it from there, depending on how challenging you want an encounter to be.

When in doubt, just look at their track record and go from there.  Don't be afraid to pull out bigger guns (literally or figuratively) than you think you'll need, because you've just got one brain thinking up tactics, and the players have several;  also, they've always got Edge, so even if you up-gun the opposition too much, you can generally count on your PCs to find a way to survive. 

Don't forget the intangibles:  cover, smoke grenades, darkness modifiers, that sort of thing can all really decide the fight, not just the starting die pools involved.  You can run two very different-feeling fights with street-level gangbangers waving around submachineguns compared to a slick corporate kill-team with the same weapons -- giving both groups of NPCs the exact same stats, but different appearance and tactics.  The devil's in the details, and so is the challenge level of the mook-fight. 

[Joush]

My method is pretty primitive. For non combat encounters, find ways you want them to be able to do it then figure that they will get 1 hit for every 3 in their dice pool.

Want them to be able to talk their way past a guard? Make it threshold 3 if someone has 9 dice. Expect them to surprise you and come up with different ideas then what you thought of, so stay flexible.

 Fix up a chump combatant that is weaker then the group, and an elite combatant that is more effective and at least has the same number of initiative passes as most of the group, but still isn't quite as good.

Throw enough weak foes at them to give everyone a target and someone targeting them, then have the elite combatant try to engage the most powerful characters.

Occasionally throw a much more powerful foe, like a combat drone or elite solider at them, with backup.

Busting up the weak foes lets them see how strong and effective their characters are. The elite foes give combat specialized characters a chance to shine, and gives a reasonable threat to other members of the party, while the bosses make for the fights where everyone has to work together to bring something down.

Weak examples: Basic gang members, thugs, attack animals, low cost drones, basic security personae. Either pistols, machine pistols or shotguns with flichettes are good weapons, 4 to 6 armor, 6 dice for attacking and 1 IP if your group mostly has 2 or 1, and 2 if your group mostly has 2 or 3. If your group mostly has 4, these guys should flee from every fight.

Elite examples: Armed response team, heavy corpsec, hardened gang members, transgenic critters, well armed drones. No grenades, heavy weapons or Stick and Shock rounds, but otherwise give them what makes sense (mostly assault rifles). 8 to 10 dice for attacking and armor, 2 IP's unless your group are badasses, then go with 3.

Boss Examples: Street Samarui, Rigger in Drones, elite corpsecurity, crime boss enforcer, pissed off high threat sapient critter. Unlimited weapons, but stay aware that grenades can quickly deal damage to the whole group and aren't fun when they airbrust all around. 12 to attack and armor, 3IP's. Give them one trait that stands out a lot, like a viciously powerful attack, 6 more dice to attack or armor, or another IP.

[Phylos Fett]

Personally, I like to play it organically. If the 'runners seem to want to tangle with gangers, they'll walk all over them, and things will get easier as the runners get more experienced. If they want to tackle top-level HTR guys straight from CharGen, then the runners should get wiped out. All of them.

If you're not sure, you can always back-up ready to be called in, or some of the numbers called away to deal with another threat, but if you do this too often, the runners will come to expect it.

[corax]

When learning to gauge challenge levels on combat encounters consider having a badass npc along with the team as 'backup'. he may be like the new rambo movie, everyone expects him to stay with the van but if the team is in over their heads through no fault of their own bust him out to level the field.

Don't make him to common of an occurence though or they will rely on him.

[Joush]

Oh, of course Phylos Fett is right, organic establishments of threats works.. but if you create a mission where they are expected to encounter certain types of resistance, it's good to know what will give a group a good fight without overwhelming them.