Should I make my research students' pay contingent on completion of tasks (such as reading/summarizing papers)? I received a fund that I can use explicitly for paying graduate (master's and doctoral) students for research. These students already receive a stipend from the university, but most advisors who can afford it pay them a supplement. My colleagues just pay a fixed amount per month. However, I am inexperienced in advising students, and I fear I might end up wasting the money on students who do not do their job.
So I thought of making the payment contingent on some research-related task. I do not want to make it contingent on actual research results, since the &quot;flow&quot; of results (particularly in my field - theoretical computer science) is not constant, and the students need a reliable source of income. Instead, I thought of paying the students for reading and summarizing papers and books related to their research topic (up to the maximum amount I can pay per month). There are several reasons:

Reading is an important part of research.
Most fresh graduate students do not read enough - they prefer to program. They need an incentive to start reading.
Reading is a relatively &quot;stable&quot; activity: by putting a sufficient amount of effort, the student can guarantee a fixed income for themselves.
Summarizing research papers will help the students once they start writing their own papers.
The summaries can also be useful for me during teaching, as supplementary material for the students.

Is it reasonable to pay research students based on reading &amp; summarizing papers, or for other activities?
Clarifications:

The basic income (before the supplement) may or may not be enough to live on. For students who come straight for undergrad, many are young and still live with their parents. During undergraduate studies they had to pay tuition, so the very fact that they now study for free (even before receiving any money) is a substantial upgrade for them. Other students are older and have children; for them, the basic income paid by the university may be insufficient.
Do not do this. At best, you will appear merely stingy; at worst, perhaps financially abusive. (I also suspect your university would not even allow it, but I think that's not as important because it should not be done anyways)
I strongly, strongly advise you to reconsider how you think about students. It seems you are thinking about them like employees you want to squeeze some work out of, with some sort of benefit that you deserve for providing funds. This thinking is wrong, and leads to many of the student horror stories here about abusive advisors.
A student should never be under threat that their financial security is subject to the whims of their supervisor on a regular basis. Any process that leads to a student getting paid less than their full salary* should be a structured process with warning and opportunity for improvement. You write that &quot;students need a reliable source of income&quot; - exactly, so don't make it unreliable.
Students in research are not mere employees, they are future researchers for whom you are taking on a responsibility as an advisor. You pay students so that they can focus on their research and education. You pay students who you think have good potential as researchers that are worthy of your time investment. You are not paying them to do a job, you are paying them to learn.
If you think you need to add incentive for students to focus on things like reading, do that incentivizing outside of the regular compensation structure. One option is to have regular meetings where students present papers or literature reviews of a subset of papers. Students are typically quite motivated in that setting to look good in front of their superiors and peers and they will put in the effort. You could also use a bit of peer pressure to offer some sort of group reward, like buying lunch for the whole group when a student wants to schedule a presentation over lunch to summarize what they have read (harder to do now during pandemic times, but hopefully that won't be permanent).
I'm glad you've asked about this here before implementing it, because I cannot stress enough how bad this would be.
*Exceptions: for someone who is a part-time employee, like an undergraduate student, there is nothing wrong with hourly compensation, but it should not be based on production but rather on time worked. You can decide at the end of a semester if it's worth taking that student for another semester. There could be graduate students in special circumstances that work and study part-time; they should be paid a salary relative to their part-time level of commitment.