Here I'll list my criteria for writings letters or serving as a job reference.
I have sample letters at the end of this document.
Almost always when I am approached by an employer in this regard, the firm has already concluded that your technical qualities are good. Instead, they want to know about your character: Are you ethical? Reliable? A team player? Etc. I answer as best I can, given how well I know you.
I tend to write detailed, very informative letters that may greatly enhance the applicant's chances of being accepted. I have a very good "track record." However, I must make clear a number of points.
Who is eligible?
A letter to any school that says, "Ms. Brown got an A in my class, but unfortunately I don't remember her and can't say much else" is rather useless to the admissions committee of the school.
Restrictions and disclaimers:
Please note the following:
Please let me know if you have any questions. By the way, below are redacted past examples of actual letters I wrote. Of course, some were for exceptionally outstanding students, so don't worry; I do write letters for "very good but not exceptional" students, as you'll see.
These are real letters, with names and some other information redacted to ensure that the identity of the student is not revealed. (I may place a similarly redacted summary of your letter there too.)
Letter:Letter:I'm delighted to write this letter recommending X. I've known him since [date], when he enrolled in my course ECS Y on the topic of Z, and he also did a great job in a research project with me.
X has taken two CS courses from me...These courses go in two different directions, the first in mathematics and the second in programming. Thus it is significant that he earned A+ grades in both courses...
X's exam grades placed him as one of the top two students in the first course, in an enrollment of about 70. The other top student was a graduate student, and had had previous exposure to the material in his undergraduate days...In fact, there was another graduate student in the course, actually in a math program rather than CS, who did not do quite as well as X...
In the second course, X had the best exam record by far among the approximately 50 enrolled, including one graduate student whose research area is the subject of this course!...
I gave Extra Credit for those homework teams whose programs are among the three fastest in the class... and X's team (of three students) was usually in that winner's circle...
X is soft-spoken but speaks with confidence, and made a number of deeply insightful comments during lectures.
I had funding for a project whose goal is to develop software that does W. In hiring students to work on the project, X immediately came to mind, and I was pleased when he enthusiastically accepted my offer. Software is more than writing code; the overall structures and design can be a real challenge to do well, and X really excelled here. His code is still being used today, well after he left the project for grad school, and I continue to appreciate his first-rate design, which makes modification easy.
In short, X is a truly outstanding student.
Letter:I am delighted to write this letter in support of T, whom I know quite well. He is a top talent, and is a pleasure to work with. I first knew T when he was a student in my course [Z] Since then he was worked on two research projects with me.
T was the best student in the course Z. I give weekly quizzes in lieu of midterm and final exams. The quiz problems range in difficulty from the straightforward to the challenging. They do NOT measure rote memory. formula-plugging and so on. T had the top quiz average in the course, out of about 50 students.
T's performance in my class of course is quite impressive, but to me his strongest recommendation for grad school is his invaluable contributions to two research projects that I've led...
It's one thing to write software with an agreed-upon goal in mind, but quite another to develop good goals in the first place. This is precisely what T did...[showing] excellent creativity and insight. The project group submitted a paper to [conference Q]...The paper was accepted, and T gave the talk, which was very well done. Actually, the session chair took T aside later and told him that his talk was the best of the session! Since the other speakers were professors and graduate students, this was quite a compliment.
Letter:Y is one of the most remarkable young people I've met in my long career in university teaching.
Y took two courses from me: ECS 132, an undergraduate course in probability and statistics for computer science students in Fall Y, and then ECS 256, a graduate-level course in the same area, in Winter Z....She earned A+ grades in both courses, but that tells only part of the story.
I have open-source, self-authored textbooks for every course I teach. In ECS 132, Y stood out even before our term started, as she came to me beforehand to give me a list of a dozen or so typos she had found in my book! One doesn't encounter students with such initiative every day. She then of course did extremely well in the class. I give weekly quizzes (no other exams), and Y had the highest average quiz grade in my class of over 60 students. This means, among other things, that she even outdid several graduate students from Statistics.
Y continued her stellar work in the 256 class. Of course, most of those enrolled were graduate students, and yet Y, as an undergraduate, outscored almost all of them. And, as a "bonus," she was the only one of the 30+ students, both American and international, who knew the meaning of the word triage when I happened to bring it up one day in class. Pretty nice for a non-native speaker of English!
My courses stress genuine insight; there is nothing of the "formula-plugging" nature whatsoever. Those quizzes include some quite challenging problems. For Y to shine in such a setting tells me that she will do top work in graduate school. She will make a great research student, and would serve as an excellent teaching assistant. I give her my top recommendation.
Letter:X has taken three courses from me, first a computer organization class, then one in parallel processing and finally one in scripting languages. He earned grades of A- and B+ in those first two courses, and will likely get a similar grade in the third (which I am currently preparing grades for)...
I give heavy weight to group work, with students doing the programming assignments, the last quiz and the project in their groups of three or four students. X has tended to do B work on my quizzes and exams. However, he works well in his groups, and I've observed that he actually serves as a natural leader in his groups.
The final weekly quiz consists of in-class programming in groups, with the code sent to me via the Internet at the end of class. In the parallel processing course, there were about a dozen groups yet X's group was one of only two to actually get their code to work, in a difficult problem.
X is outgoing and well-liked. He'd make an excellent TA.
Letter:I'm delighted write this letter recommending Z.
I've known Z for a little more than a year now. He took my class in [year, quarter], and he and I have interacted quite a bit since then. We've talked a lot about various subjects, including societal issues...
The course Z took from me was ECS 50, a lower-division class on computer systems. Most students regard my version of the course to be quite difficult, as it requires analysis. Up to that point, they've just taken programming classes, and the rote-memory types do poorly. Z earned an A+ grade in the course.
I've not observed Z in mathematical settings, but I see that he earned an A in a number theory class in the Math. Dept...
Z's salient quality is his earnestness. He is keenly interested in the workings of society, and wants to Do Good, contribute to the world...
On a personal level, Z is highly articulate...and is outgoing but not flashy.
I do believe that Z will make his mark on the world, and I strongly recommend him.
Letter:I am delighted to recommend Y for the position of [student leadership position]. I have known Y for about a year now, both as her professor and her faculty adviser. I think quite highly of her.
Y is a very exhuberant and outgoing individual, unusual among engineering students. She is quite friendly, very popular among her classmates, truly enjoying interaction among people.
Y is very much a "go-getter." A good example of this concerns her participation in the Society of Women Engineers on campus. Y has worked very hard to recruit more membership into the organization. As someone who has himself worked very hard to get more women into engineering, I consider Y's work here of great value.
I am quite sure that Y is headed for a fine career involving leadership in some form, either as an engineering manager or maybe even as an entrepeneur herself. Thus she has exactly the personal skills appropriate for this position, and I highly recommend her for it.
Letter:...R earned an A+ in the class. He was one of the top two students in terms of examination scores (he and the other student were essentially tied, substantially above the rank-3 student), and made excellent, insightful comments in class.
The term project is done in groups of three or four students. The one submitted by R and his two partners was truly outstanding, possibly the best I've seen in the dozen or so times I've taught the class...
All of R's team for the project were top-notch students. (One was the one he was tied with for top exam scores.) But they all contributed equally to the project, according to the statement I required of all students, and I am quite sure that is true.
R's research with me has involved [software topic]... it appears so far that our package...is substantially faster and easier to program in than various alternatives.
Letter:I am delighted to recommend W for doctoral study. W took ECS 132 from me, a course in probability and statistics for computer science students.
ECS 132 is a very difficult course to teach, because many undergraduate computer science students lack math intuition, a crucial skill for both success in the course and the ability to apply the material in one's career and indeed one's life. I hope it is clear from my phrasing here that I consider this course to be of very high importance...
I must say that this will be an unusual letter. Did W get absolutely top exam grades in my course? No, just a respectable B+, though with two or three of his grades on my weekly quizzes being A+. Has he done research with me? No. Do I know him exceptionally well on a personal level? No. But in spite of all that, I believe that he would do quite well as a PhD student.
W did visit me in my office on a number of occasions. But instead of asking for hints on the homework, as most students do in my office, he asked me a number of conceptual questions about the course material --- penetrating questions. I remember being taken aback on several occasions by the depth of what he was asking. He had extraorinary insight. It is on this basis that I rate W quite highly. I realize that this is an intangible, but I have strong confidence in my statement.
W told me, when he was in my course, that this was his second Bachelor's degree, the first being one in [the humanities]. How's that for shifting gears! I would guess that it took him a while to adjust to the engineering "culture" in taking exams, hence the disparity between the keen insight he showed in my office and the generally more modest level of his performance in my exams.
On a personal level, W is unusually quiet and serious...He is quite well-spoken, though, and would make a good TA. And if he were in my own graduate program, I'd be happy to take him on as a research student.
This is an unusual case, one that in my opinion calls for unusual assessment. I definitely recommend W for your program.
Letter:I know L much better than I know most of my students. He took two classes from me...and we've had a number of conversations about computer science and statistics.
Many students have excellent grades but only shallow insight. L is not like that at all. He has excellent insight, and is definitely a Thinker. It has been a pleasure to know him. I would be thrilled to have him as a research student.
Letter:G was a student in my ECS 132 class...a calculus-based course in probability and statistics for computer science students...Most students find the course difficult, at least in my version of it, as they sorely lack mathematical intuition.
G earned a high A grade in the course...The weekly quizzes are challenging, and her average score was easily among the top five or six among the 80+ students enrolled.
[It] is especially noteworthy that in Quiz 4, G was the only student in the entire class to correctly solve one of the problems, which dealt with recurrence times in Markov chains...
G later worked on an undergraduate reserch project with me, developing open-source software. The algorithm is quite intricate, and writing it required an especially high talent in abstraction. Her programming skill is absolutely first-rate, and she contributed many ideas to the project.
Letter:[A few weeks ago] C approached me in Fall 2021 about the possibility of doing research with me. I asked her to meet with me to discuss it.... We talked about the [research] problem, touching on various stat topics, such as sample size, regression models, linear algebra and the R language. It was clear to me that she had learned well, and unusually for undergraduates, she had retained it. She followed my discourse on the general [research] area well, and immediately understood the new methods that I suggested she and I might explore.
And C's unusually high level of enthusiasm evaporated any reluctance I may have had about taking on one more student. It was clear to me that she not only would devote the time needed, but would do so with great energy and a high degree of intellectual curiosity. There were many instances in which I mentioned some side topic, on which she immediately wanted to learn more. In short, the project would be an enjoyable and very productive collaboration, so I happily accepted her as my research student. It has been a pleasure meeting with her in our weekly interactions.
The project is empirical in nature, not theory, and I have not had her in a class. Thus I cannot comment on C's math skills on a theoretical level. She has shown good intuition, such as in the discussion she and I had back in October on overfitting. Of course, intuition is key to the project.
It's a pleasure to write this letter recommending R, an outstanding student.
I've known R for almost a year now, first as a student in my course X, and later in his participation in a research project with me, which is still ongoing today. I will focus mainly on the latter, as I've come to know him quite well in that endeavor, during which I've developed the highest respect for him.
R earned an A- grade in the course. That put him in the upper-third of that class, which is impressive in that it is one of the best groups of students I've ever had in terms of student participation during lectures. There were many lively, quite enjoyable class discussions on the nature and ``philosophy'' of machine learning, something I rarely see in our students. (R himself was usually not involved in those discussions -- he preferred to discuss with me during office hours --- but the point is that it was an especially strong group of students.)
But where R has really shined is the research project. Actually, this started rather by accident. Another student was starting the project, and while I was meeting with her, R happened to drop by. On the spur of the moment, I asked him if he would like to join, as he had indicated interest in doing research. He did join, and he and the other student immediately started doing excellent work. The other student was in her last quarter, and after she graduated, R has been working by himself. It has been a delight to work with him, and I look forward to our weekly meeings.
The project involves use of machine learning for Y... The key skills needed are strong coding ability and keen geometric intuition, both of which R possesses. He has worked mainly on his own, with very little direction from me, and has come up with good ideas.
At this writing, R and I have a paper on the results... That paper includes some empirical investigation of the method, with some promising results, and he is now doing broader and more thorough experiments. We hope to submit this broader work to a strong journal or conference within the coming months.
R began his career here at Davis as a non-STEM major, then transferred to Computer Science. He has earned A or A- grades in all his courses in my department, mostly from some of our more challenging and demanding faculty.
R speaks completely fluent, American-accented English. Though he is an international student, I would guess he spent some time in American schools during his formative years. He also is outgoing and has a kind demeanor. He is the type of person who earns high respect from his peers. If called upon, he will make a popular, very effective TA, and will do quite well in presenting research talks as a grad student. In summary, R is bright, energetic and articulate. He will make a fine graduate student, especially in research.