Let me start by saying that I love my upper-level undergraduate students. They are engaged, enthusiastic, willing to try anything, hard-working, and asking great questions. I have near perfect attendance in my class, and when a student misses class, I usually hear a pretty legitimate excuse, often with documentation. Our students have complicated lives.
But it pains me when students miss hands-on labs or field trips. I want them to get the educational experience of the lab/field, and I don't want to penalize them because they were prostrate over the toilet with the stomach flu. (Boy, has this been the winter for stomach flu - some of my colleagues have had it three times.) Paper- or computer-based labs are fairly easy for our students to make-up. I give them the lab hand-out, give them a suitable extension to the deadline, and tell them to ask me when they need help. But what I'll call "wet" labs, where we are working with specific samples and techniques, usually require setting up equipment, procuring samples, etc. These labs get set up the afternoon before lab and cleaned up immediately after the students are done, because other classes use the same room. So if a student misses a wet lab, I either need to go through the whole set-up/take-down process again (often several hours of my time). If a student misses a field lab, it could mean a whole afternoon or even a whole day of my time to go out in the field with them. Or I could send the student out on his/her own with no hands-on guidance and no one watching out for his/her safety in the field (a real concern). The alternative to recreating the lab/field experience is to give them some sort of easy-to-assemble alternative assignment, but I often feel like the alternative assignments (write a paper...) don't meet the same educational objectives as the original experience. Plus, it's difficult to feel fair grading an entirely different assignment and throwing it into the same grade pool as the rest of the class.
This semester I am teaching a class that is lab and field intensive. We are doing wet labs or field work 10 weeks of the 14 week semester. So I've already had a few missed labs to deal with. I've been trying to get students into the field to make-up for missed field labs, but without overwhelming myself in the process. I took two students out to one of my field sites for a 1/2 day to help me collect preliminary data, and I called that their make-up lab. I assigned another two students to go out to a field site with each other and replicate some of the work they missed. But I've got at least one more field make-up to deal with, and we've still got ~5 weeks of semester left. So I'd be curious to know how other faculty deal with make-up labs and I'd love to hear your suggestions in the comments. But when you comment, please remember that these are hard-working, enthusiastic upper-level students with complicated lives, and not freshmen who were too hung-over to come to class. They deserve compassion and a good education, but I can't be constantly on-call to create lab and field experiences on-demand.
Could you get them to come into a lab on campus and do something for you, or for graduate students? Perhaps even the graduate students could keep an eye on them, or help if needed? I don't really know your set-up, so don't know how feasible that is, but I thought I'd put it out there.
There are two parts to this. On the one hand, there is the formal issue of "have they done enough in the lab that the grade is appropriate?" I think your make-up alternatives address that.
The other is, "have they gotten the full value from the course that they deserve?" You obviously don't feel that they have.
I would suggest decoupling them. Obviously, for a senior graduating this spring your options are, as you note, rather unattractive. However, for those who will be around when you teach the class next time, you could try to offer them the opportunity to join in for the parts missed.
You might also get the "they won't be around next time" list down to the point where you could justify spending the extra time to redo with a few of them.
I recall long, long ago having one lab whose instructor insisted on all of the work being fully done. His solution was to give anyone missing a lab an "incomplete" until it was made up in full. Harsh, perhaps, but a pretty good solution for everyone except graduating seniors.
Just a comment in response to DC Sessions' suggestion of giving "incompletes" until the student does the lab the next semester or next school year: this can be really problematic for students on scholarships or fellowships. Some funding sources (like mine for grad school) will cut the student off or put them on some sort of probation if they get an incomplete, so I would say this method should only be used after you've determined how it will affect the students.
My most field-intensive class is my sophomore mapping class. I've generally allowed students to make up work by going out to the field site with friends from the class (who can show the students where to do the work, and help them with problems that come up). This works for field sites that are close to campus and don't have major access issues (like private property) or safety issues, and it's good practice for their friends to explain the techniques.
In other classes, I've sometimes excused the field work if something came up and I can't think of a convenient and safe way for the students to make it up.
I think having the students help you with your research field work is the perfect solution. Even if the techniques aren't exactly the same as the one you would have been doing in lab, they'll get an immense benefit from seeing how you collect your data, how you keep things organized and safe for your own field work, and how you think through both the science questions and the logistical problems that come up. Helping your grad students would be similar.
For the indoor wet labs - could you have students help you set up a future wet lab? Sometimes seeing how all the pieces have to fit together in order for everything to work is also useful.
Are these students who are going to graduate before you teach this course again? I don't think I would give them an incomplete, but you could invite them to join in the next time you teach the class. Some of them may want the opportunity to get the skills for future jobs, and some won't. But you could leave the option open for the motivated ones.
I don't know how feasible it is, but in the future you might also just consider building in an 'extra' lab or field trip. (e.g. of 11 labs, you must complete 10 for the credit, the 11th will count for extra credit) Mature and responsible students tend to save their 'pass' for when an emergency comes up- and it makes life less stressful all around to have some flexibility built into the system.
Is there only 1 lab section for the course? If there are multiple lab sections that follow the same lab syllabus, you can have them sit in with another section...gets a little sticky when students work with partners or in groups, but it's a good alternative if it's available.
Another alternative is to have them read and review a published paper that relates to the technique or site that you were working with in the missed lab--then they see the practicality of what they missed without putting too much time pressure on you. This option may work better for people who work exclusively at the bench with not a field site in sight.
I would also second the notion of having them help prep another lab that uses related equipment and methodology, or having them serve as extra hands in a field excursion for your research.
I struggle with frequent migraines and miss enough classes to try to avoid signing up for courses with lots of lab time - even though they're so valuable. Luckily, I've been able to work in a lab for my job (with very flexible hours) which makes up for a lot of what I've missed. If I were in your course and needed to make up a lab, I'd love to spend an afternoon shadowing/helping a grad student - even if it isn't directly related to what was happening in class. I know this could be hard - lots of things require a fair bit of training, there can be safety concerns, etc, but I think it could be fun for both the undergrad and the grad student.
Have you considered making one day toward the end of the semester be THE make-up day for all wet labs (i.e. you set up and then supervise all students who have a wet lab make-up at once) and another day be a make up day for all field trips. This seems to make more sense to me for the wet labs than for the field trips.
One other possibility: if any of the intro classes has a lab on related stuff late in the semester, you could let your advanced students make up their work by helping out with the intro class - either setting up equipment, or (better) coming to lab and helping explain equipment, techniques, processes, etc to the intro students. (You know the project that I do with my intro class - something like that. I wrangle upper-level students to help with that anyway, because otherwise I would need to clone myself to manage the five-ring circus.)
I typically make it clear at the beginning of the semester that labs are not to be missed and cannot be made up. No exceptions. This typically ensures that anybody who protests has missed lab for a legitimate reason, e.g. a death or illness in the family. You can always just not factor that particular lab into their grade.
In the real world you often can't "make up" lab work. And I mean can't, not won't. I don't think that's a horrible lesson to impart upon them, but having them assist in the setup/teardown of another lab is a good lesson for the sheer amount of time and resources that goes into an experiment.
As an undergrad, I went to a top-ranked school and there were no make-ups allowed. Ever. On anything. Everyone still muddled through.
I second Becca's suggestion that one of the fields or labs be droppable. Just say that you will drop each student's lowest score for one field/lab event, regardless of whether the low score is a 0 due to not being there, or a 75 due to being nutty that day. Then make it clear that you will not be inclined to accept any additional "excuses" for missing a lab. This will help prevent people from taking their "free" lab to play hooky, then needing a real make-up when a relative dies--not that it sounds like your students are likely to do this.
I echo Becca's suggestion: I drop the lowest lab grade and state that no makeup labs will be offered. In extreme circumstances, I'll setup an opportunity for a student to makeup a lab, but only if they've already missed one. And if they miss more than two labs, it's an automatic failure in the course.
I do something similar to what is being discussed. I have a single, optional, extra lab and then I drop the lowest one, whether it is a 0 or just a lower grade. I have found this to be the most educationally satisfying for the least work. It rewards hard working students who want to bump up their grade. It also serves as a self-regulating check. I will often work something out if someone misses two labs (with a compelling reason), but once they've missed three there is an underlying problem that is most appropriately handled with a "hardship" withdrawal.
This hasn't worked as well in field classes, where I've tried a few things. I have actually sent students out on their own and the results are really student-dependent. In some cases, it actually shows them that they can go to these places on their own and leads them to further independent recreational experiences. I have also found volunteer opportunities in the community to serve as make-up assignments. Similarly, sometimes this leads students to discover the satisfaction of community service, but sometimes it is just "filler". Still working on it.
Thanks for great suggestions!
What happened when I was at uni was that there were multiple sessions for each lab (due to numbers) and if you missed your assigned session there was an opportunity for you to attend a later session. If you knew in advance you would have a clash there were usually opportunities to swap sessions with someone else. This may not be appropriate for your class size however! I do like the suggestion of having one extra lab and dropping the lowest mark that everyone has praised so much.
Bit of spam in these comments though.