What should the course leader do if some students were given less time for a quiz? I am the course leader for a course with more than 600 students.
This semester,
I decided to conduct our end-of-semester quiz
as a computer-based quiz using our school's learning management system.
We needed to reserve multiple computer lab rooms
due to the fact that the maximum capacity of a lab room is about 80 students.

Unfortunately, 
we had always used a paper-based quiz in the past,
and it was the first time that we had ever used computer-based quiz,
so things did not go as smoothly as we would have liked.

We had requested that the students
should show up to the quiz venue 10 minutes early.
This would give them time to turn on the computers
and to log in to the quiz using
a special browser (Respondus LockDown Browser)
rather than the regular Internet Explorer browser.
Unfortunately, our instructions to the invigilators and the students
were not clear enough,
so even though most of the students showed up
to the quiz venue 10 minutes early as requested.
The invigilators did not make clear to the students
how to log into the computers and into the quiz,
so many of the students started the quiz 5-10 minutes late.

I attempted to communicate with the invigilators
to give the students 5 additional minutes to complete the quiz.
Unfortunately, due to miscommunication,
some of the invigilators ended the quiz on time
(so the students in their session had 50-55 minutes);
whereas some of the invigilators gave the students extra time
(so the students in their session had close to 60 minutes).

After the quiz was over,
some of the students who received 50-55 minutes complained to me
that they were disadvantaged because
they had less time to complete the quiz than other students.
It may or may not have been the student's fault
if he or she had less time for the quiz.


For some of these students,
they had less time because
they arrived late (which is their fault)
For other students,
they arrived on time.
However, because their computers booted up slowly,
or the invigilators did not make it clear
how to open the correct browser and how to start the quiz,
they started their quiz late by ~5 minutes
(this could have been avoided with better planning on our part).


Questions:


How should I respond to these student's complaints?
Is there anything that I should do to "fix" the situation?


Currently, I feel that the quiz was mostly fair to the students.
I am able to see in the learning management system that
fewer than 0.1% of the questions were not answered,
which means that 99.9% of the questions were submitted properly.
So although some students who had more time
had the benefit of double-checking their answers,
for the most part even students who only had 50 minutes
had enough time to complete all of the questions.
I believe there are a lot of circumstances that have to factor in to the decision, but to me, the most important initial detail is, do you have any way of reliably tracking whose time was cut short and who had the full time allotted? If not, it's going to be hard to analyze and correct the situation.

I'm assuming that, since it was a quiz, it's not a huge factor in their grade, so what I might do is either renormalize the grading or pro-rate it. Basically, if the quiz was supposed to take 60 minutes, and the most any students were shorted (by no fault of their own) was 10 minutes (still less than 20%), then the new baseline can be considered to be 50 minutes, or 83% of the original time.

To renormalize, multiply every student's grade by 1.2. For students over the new 100% mark, you could give extra credit or simply cap the score at 100%.

Or you can do a quick-and-dirty pro-rate by adding 17% to everybody's score, again, either up to a maximum of 100% or going over and giving extra credit.

I realize you have a huge class, which also implies you have a lot of early-undergrad students who might raise a bigger stink, but in my academic career, I've seen plenty of ex post facto shifting because of logistics, especially when a prof or the school is rolling out a new technological approach.