Is it possible to measure/evaluate one's progress or development in quantitative terms? I often end up frustrated over the pace of my work, or rather the lack of "worthy" results. During my feedback talks with my colleagues and superiors I usually get good feedback but I find it distressing that most of it is qualitative arguments.

I sometimes feel like I have not progressed as much as I would have liked to, but not sure how to assess whether or not I have developed "enough" over time. Which led me to wonder if it is possible at all to measure how well a PhD student is progressing.

The usual measures in the community appears to be: 


number of publications
which journals the publications appeared in (or rather the impact factor)
number of hours in the lab (regarding how "hard-working" one is)
number of credits taken from courses during phd studies


I personally find none of the above to be a good measure. Publications are a fact of research, or the goal rather. But they should not a be measure of how well a PhD candidate is doing in research. I believe the pragmatic demand on "more publications" has essentially lead to overall lower quality and novelty in individual publications. But even without that subjective comment, it should not be a revelation to anyone here that the amount of publications (and especially in which journals they are published) is more dependent on the seniors on the paper rather than the grad student who wrote it.

As for the other two measures I point to, they are just too naive variables to mean much. I mean you can be in the lab for 18h a day, but not learn much new or even worse not even remember those things you have learned. Besides one can also argue whether or not it's actually better for a grad student to be obsessed with number of hours in the lab, or courses taken. 

Summary: Is there a good way to measure your progress through-out your studies? How can I evaluate my development as a scientist, in quantitative (and unbiased) terms?
To reduce anything to a quantitative score, you need a valid metric. There are very few valid metrics you can use in research, as you state in your question. The only other half-common metric that you didn't list above is Papers read/annotated. We all know reading is really useful, and you should definitely aim to read X papers a week (where X is some random number that makes sense in your field). That said, the goal of reading is to gather information, and how much information was gained (and retained) is a lot harder to measure.

That said, I have two half-answers:


Make up your own metric based on hours of productive work. At the end of each day, just write down in an excel sheet or something how many useful hours you worked that day. You can use some service like Rescuetime to help you in this, or the Pomodoro technique, or just simply buy a stopwatch and keep track yourself. At the end, do a simple # useful hours/total hours worked to see how productive you think you're being. That'll probably be more useful than anything else you'll come up with.
Make task-specific metrics. I tracked my progress on my thesis using a custom shell script I wrote that tracked how much text I added in a given time period and plotted it out. (Yes, I probably spent more time making the shell script than I gained in motivation from using it. Whatever.) I tracked progress on one of my projects by how many datasets I had analyzed. I tracked progress on another project by how much coding I completed each day. These are much more useful than broad, overarching metrics.