Inside My PhD Qualification Experience

In the period leading up to and after my qualification exams, I found one constant, that there are no other constants about what they were. This began with talking to European colleagues who were surprised to learn that even though I was finishing my third year of a PhD program, I still wasn’t a PhD candidate. In the US though, that is completely normal, but there is still uncertainty about what exactly the exams entail.

In general, qualification exams occur when a student is nearing the completion of their coursework. The exam(s) are meant to gauge whether the student has obtained all the knowledge required. If there are gaps, they will be clear, and the graduate committee will recommend further study before attempting the exam again. However, the content of these exams differs between universities, departments, and even professors.

A mere glimpse into the different exams.

A University of Florida physicist got a series of take-home exams of physics equations. An astrophysicist joined her cohort for a timed in-person exam of a similar nature. For those departments, the questions asked were very directed to what makes them a classically trained member of that specialty. In some cases, such as those, they may all have similar questions to others regardless of their research topic. It is expected that there will be an oral presentation followed by questions for each student though.

In the Agricultural and Biological Engineering department, individual committee members have lots of leeway in what they ask and how they want the student to respond. I have heard stories in the department of those who had to write full mass balances of chemical reactions, design an object, analyze a relevant dataset, and even write lessons. I can’t speak to all their experiences, but I can share mine with you!

What my exams looked like.

Before the exams I had to submit an updated version of my research proposal to account for any changes to methods, and what I had learned or accomplished over the last 3 years. This gave my committee a clear view of everything I was working on and gave me a pretty good start on the first draft of my dissertation. Looking at the written exams and this proposal it is easy to see how some of the committee members came to ask their questions during the oral exam.

It was not uncommon for people to suggest that you shouldn’t stress out about quals, that you only get to take them when you are ready, and that you should already know everything you need to know. They were not wrong about any of that, at every exam I sat down and let the answers pour out, the hardest part wasn’t knowing the material, just presenting it in a complete, intelligible format within my allotted time.

My first one was only three questions surrounding crop modeling. It started with a discussion on incorporating root zone conditions into the Modified Energy Cascade (MEC), which is currently lacking. Then a one-page proposal on using the MEC to manage greenhouse climates. Lastly a “non-exhaustive” literature review about trends in crop modeling, including machine learning.

My second day of quals was entirely different, as I was asked to create a lesson about stomatal conductance for an undergraduate course. Learning objectives, background, a causal loop diagram of factors affecting stomatal conductance, a simple model as a learning tool, and activities to go with it all. My final product included all that along with the accompanying PowerPoint and lecturer notes.

Day three was also unexpected. At 1,000 words max, it was my shortest response because it was to write a popular science article about climate change, resilience, indoor farming, and photosynthesis. Conveniently, this was exactly something I was thinking about trying to do already!

The last written exam was straightforward beginning with an introduction to the global sensitivity and uncertainty analysis I was conducting before it delved into interpreting the results. The last half focused on understanding the importance of the results, the implications for model refinement, its applications to CEA practices, and future research directions.

The oral exam usually was scheduled for a week after the last written test. Admittedly, mine went differently with questions arising frequently throughout instead of all at the end. Some may find it stressful to stop and start like that, but I found it useful as we could focus on what was important when it arose and skip around as needed.

Reflection on the process.

The oral exam was the hardest part as my committee dug into my knowledge to see what exactly I knew and proposed. Some moments were amusing and educational, like when I was told I had successfully described the drought response of an olive tree, which behaves the exact opposite of lettuce. I won’t be forgetting the difference between anisohydric and isohydric responses anytime soon. Other moments were difficult and humbling such as admitting to not understanding the underlying mathematics of a specific analysis method.

During the deliberation, while I waited outside, I found myself running through the questions and answers. For once, feelings of both inadequacy and confidence were simultaneously set aside, I could see where I was clearly excelling, and falling short, with no doubt that my committee could too. It was a brief relief to hear that I had passed, overshadowed by the need to begin planning how to improve and address my shortcomings that were laid out clearly during the whole process.

Purposeful examination.

Overall, it was one of the most demanding experiences I have been through. The exams were lengthy and taxed my brain heavily, with little reprieve. In the end, though I wrote some important things that will end up in manuscripts, a lesson that may come in handy sometime soon, and a popular science article that is being further developed for publication.

I can’t speak for what quals are like everywhere, but the flexibility afforded to my committee gave them an opportunity to simultaneously test my knowledge and produce useful material for my degree and beyond. It pushed my understanding and application of the knowledge I have gained over the years into multiple formats, not unlike the expectations put on professors these days, who balance writing manuscripts, proposing research, teaching, and participating in outreach.

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