How can I motivate the teaching assistants to grade more strictly? I am a lecturer in charge of a course with over 250 students and several TAs. The TAs are partly responsible for grading the homework assignments.  Since these are assignments in programming, no two submissions are identical, so it is impossible to cover all possible cases in the grading guidelines, and the grading has some subjective element.
I noticed that one TA is consistently stricter than the others. For example, if the guidelines say that &quot;code efficiency&quot; is worth 20 points, then this TA would deduct 15 points when the code is inefficient, while the other TAs would deduct only 5 points for a similar issue.
A potential problem here is that it might be unfair to the students in the strict TA's class, but this can be solved by allocating the assignment task &quot;horizontally&quot; (each TA grades all 250 submissions in some of the assignments) rather than &quot;vertically&quot;.
But I have a different question: I noticed that students who are graded more harshly, take the feedback comments more seriously, and tend to become better programmers. So, rather than just being &quot;fair&quot;, I would like all TAs to grade in a stricter way - for the sake of the students. The problem is, most TAs are not motivated to grade strictly - they gain nothing from it; all they get is having to  handle students' complaints and appeals, and risking lower marks in the students' feedback (since the students do not understand that it is in their favor until after they graduate).
The TAs are not lazy - they do put a lot of effort in teaching and helping students; they just don't like to be the &quot;bad guys&quot; who give low grades. How can I motivate them to give stricter grades?
You have a bigger problem than encouraging stricter grading. You need to provide consistent grading. Otherwise your scheme is fundamentally unfair.
For starters you don't have an option to fail to provide a proper rubric. If you aren't doing that, then you are failing the students. If it is a lot of work to do it, then you have a large task, but a required one.
You can make the rubric as strict as you like (though I don't really like the concept of narrow interpretations), but it has to be clear to your TAs and it has to be reasonable to your students.
One way to assure some consistency is to have more than one TA involved with each student's work. They need to agree with each other or appeal to you for a judgement. If they enter student grades into a spreadsheet you can easily see the differences and can also use it for further TA training as needed, such as, for example when one TA is consistently &quot;too&quot; lenient.
For an exercise with lots of parts, it might be possible to have each TA responsible for only one part. This tends to work for final exams where students answer questions, but less well for programming assignments.
Another way to achieve a good rubric is to have yourself or a small team of advanced TAs scan the student work without grading it and use what they learn to refine the rubric to assure consistency. It is probably a mistake to use this trick to create the rubric in the first place, but it gives you an idea of where the students are going wrong and need correction. An overall view. Once that is in place, the actual grading can occur.
Another trick, though not very easily done in pandemic times or with a large pool of graders, is to bring everyone together in real time to grade all the papers. This could possibly be done online (zoom) and you could be present to answer questions and make decisions.
But, again, consistency is a requirement. The rubric needs to be complete to assure that. The &quot;strictness&quot; is a secondary concern, but could be improved (your idea, not mine) with a proper rubric that everyone finds clear.

Moreover, if you try to grade things on a fixed scale that are fundamentally &quot;fuzzy&quot; then you have an impossible task. If you can define &quot;efficiency&quot; in your example, then fine. But if it is a fuzzy concept then almost every rubric is likely to leave the grading to intuition. Give precise grades on the things that are precise. But for other things, judgement and a bit of compassion are probably needed.
In CS, some things are clear, of course. If a student uses bubble sort on a large array it is clearly inefficient. But selection sort is more efficient than quick sort at a certain scale, which is why library versions of quick sort normally drop back to selection sort for small sections of the initial set.
But judgments about &quot;proper factoring&quot; of code are judgmental. If your feeling is &quot;I can't define it, but I know it when I see it.&quot; then it is nearly impossible to provide a rubric that will be used consistently by a group of TAs.