Which works better, the carrot or the stick?

From your description, it sounds like people are enjoying the classes a lot, and you're getting new people. That doesn't sound it's broken, so it doesn't need to be fixed. If you try to hassle people for not coming you're going to see a dropoff in attendance, and if your goal is to find new people, that would be bad. Your other problem is getting trained people for shows. Here I think it's perfectly reasonable to have a policy where only people who come regularly to the workshops are considered for the performances. If your policy for the shows is "any warm body", then there's no downside to skipping workshop.

There are currently no penalties for missing class. It's not like they forfeit a portion of their tuition money that they've pre-paid, or that they get put on "probation". This is the source of your problem. If people subconsciously know that nothing happens if they slack off, they're gonna slack off. I realize that you don't want to shut them out entirely, but how about a demotion? If it's the lead who keeps slacking off, demote her to a smaller part and get the other chick who's been showing up on time reliably. Yeah, maybe the other chick isn't as empirically talented, but she shows up and does the work, which is actually a larger part of the battle. I know you want the best possible show, but a consistent rehearsal schedule is going to be what does that, not the constant shifting to accomodate flighty-but-talented people. Talent does nothing if the work doesn't get done. And I've also seen time and again that performances benefit from someone REALLY strong being in charge. If there isn't someone In Control, people can get a little uneasy. You laying down the law finally may also be what finally brings some people around.

The Harold is just the format; performing it requires many skills that need to be grokked and honed before it can be amazing. So lovedbymarylane's good advice is still appropriate: Let people know this week you're working on edits and narrative, while next week you'll be working on characters. Also, there's a difference between coaching or teaching new skills and directing. If you're just drilling skills all the time without actually rehearsing, it's going to produce a sloppy product. Conversely, if you're trying to rehearse with performers who haven't had enough education to get through rehearsal without remedial coaching, you're all probably frustrated--and the audience will be too. Have you considered separating your interests from your goals a bit? Plan a 3-person Harold show on x known date with known performers. Rehearse them. Then hold a drop-in improv salon every week for whoever's interested in just playing around and/or learning new skills. Lastly, have you considered whether you have spotty attendance because, although people might be interested, you're not effectively teaching the skills you yourself learned? Could you find a mentor, either to help you teach or direct? Improv folks are generous, and I'm sure you could at least find someone more established to email with.

I wouldn't recommend penalising people, as unless you are going to charge huge amounts (and then how are you going to actually get the money? Send 'the boys' round?) then people will actually see it as more OK to miss a session - after all, they are paying for the privilege. I would charge an upfront fee (not a deposit - if you don't want to keep the money then use it to buy refreshments or something- say it's for admin costs, whatever). Charge for a set number of sessions. Don't change any arrangements for people - they should be planning round you, not vice versa, and it's not fair on those who always turn up. If you really feel there are people who can't pay, deal with them privately and let them off. You don't have to charge loads, it's just that people don't place any value on stuff that's free. Look at how much better MetaFilter is than so many other websites, and I'm sure a lot of that is due to the 'entry fee' - which is basically neglible to your average Westerner, but sets some barrier to participation and gives the product value in the eyes of users.

How are your sessions structured? I would consider naming what you're going to focus on in advance, so people know that they'll learn a particular skill in that class and it's not just going to be the same old warmups, short form games and a long-form game at the end (as fun and useful as that is!). You might start with 'Spontaneity' and then move onto 'Narrative', 'Character', 'Song' etc. People might be less likely to miss a session if they know they'll be learning a specific skill that they can't just pick up on the next week. I think the problem with impro training sometimes is that the line is blurred between 'fun times for two hours' and 'learning a skill'. This is especially so if you're not paying for a course. I wouldn't feel guilty about missing two hours of fun times to finish an assignment, but if it was a 'course' and I knew I was missing a lesson I couldn't make up, well, I would make sure that assignment was done beforehand.

lovedbymarylane: I'm basically presenting multiple years of longform training I picked up at the "famous" improv training centers in Los Angeles: the Upright Citizens Brigade, iO (Improv Olympic) and Second City. The lesson plan varies, but the takehome message is "we work on the Harold, as a group, until it's amazing". There's always room for improvement, as the group is only as strong as its weakest link. Which might sound boring, but I assure you it's not. It's all anyone does in Chicago, NYC and LA, for good reason. We're doing this in Melbourne, if you're interested -- I see you're in Ballarat. We have 4 shows in MICF (starting next week) but the goal is to do a full run in the Melbourne Fringe in September/October.

Hey, From experience with similar activities I can tell you that the problem is not with you. People just don't always show the kind of dedication you're looking for. Sure, they have fun when they're there, but that, for them, doesn't mean they're going to be there every time. It's just something they like to do, an activity they enjoy as much as, say, watching a movie, so sometimes they're going to do the one and sometimes the other. I've been (still am) in your position and it really, really sucks: you're pouring your heart into this and you feel like they just don't care or even that they're using you, but it's just a matter of looking at it differently; it's not ill will and it's not something you can change. You'll just have to accept it or quit teaching, because otherwise it's going to eat at your relationship with these people.

We're doing this in Melbourne, if you're interested -- I see you're in Ballarat. We have 4 shows in MICF (starting next week) but the goal is to do a full run in the Melbourne Fringe in September/October. Whoa, small world! I'm fairly sure we've met AND I've seen you perform (I'll memail you my secret identity). I will be over in Melbs for a lot of the comfest so I'll most likely see your show - best of luck getting your troupe together!

I have the exact same issue with my choir - I have a core group of stalwarts that come all the time, a few who miss practices here and there, and some who are complete flakes. If what you're running is volunteer, then there isn't much you can do to force them to come to practice or even to a performance - you don't have a lot of stick to beat them with if the carrot isn't working. For me, and other choir director friends of mine, the solution is to have a larger group than you strictly need. Then, in performance, you have a strong core of good singers, and maybe a few hangers-on who aren't as good 'cause they didn't put the work in. For you, would you consider a "junior" and "senior" improv team? Those who have come regularly to practice and are solid performers are in the senior team, with the less experienced performers in the junior team.