I recently conducted reviews of over 100 University of California essay drafts from my students, Redditors, and followers on social media. It was the first time in a while that I’ve reviewed such a high volume, and my findings were quite interesting. Students from the United States, Europe, East Asia, South Asia, the Middle East, and South America shared their essays with me. But even among this diverse cohort, I noticed some striking similarities in their essays.

In the past I’ve praised ChatGPT’s writing ability, especially for college admission essays. But it has a limited conception of what makes for a good essay, and with an uncreative prompt, it tends to make a “safe” choice, which is often clichéd. As I frequently emphasize, context is important. Your essays do not exist in a vacuum, but among the hundreds of thousands or even millions of essays out there. That’s why having a “good” essay is not enough.

Generative AI works by training on vast amounts of data. When prompted, it will make use of that training by predicting what would fit the prompt. It is by definition answering the way many have answered before. Every GPT comes with biases from its dataset, and ChatGPT (and Claude) have their own.

I’ve been aware of some of them (unique punctuation, mutiple endings) for a while, but the other things are most recent discoveries.

Here are what I consider the seven biggest hallmarks of ChatGPT:

1. Vocabulary

I'm not going to go into much here, as a lot has been written about this. There are certain words like “delve” and “tapestry” that are far more common in ChatGPT-written essays. But vocabulary as a telltale sign is also context-dependent. Based on my experience working with certain student populations (particularly students from India), I've been seeing words appear that a particular group would never use.

2. Extended metaphor

This is an example of something already fairly common in human-authored college essays, but which ChatGPT uses in a limited number of ways.

I want to offer some perspective: it's mind-blowing that ChatGPT can understand and generate sensical metaphors. It's one of the most significant achievements in AI to date. But the metaphors it uses are usually not very original. Common ones include:

• Weaving (especially the aforementioned tapestry)

• Cooking (all the ingredients with their own unique flavors being mixed with care coming together to create something delicious)

• Painting (so many colors!)

• Dance (who doesn’t love graceful coordination? Animals do it too!)

• Music (it has a clear preference for classical symphonies. It's never ska, reggaeton, or arena rock!)

3. Punctuation

ChatGPT has some idiosyncratic default punctuation behaviors. For example, it uses straight quotation marks for quotes and straight apostrophes for contractions, but curly apostrophes for possessives. It also defaults to em dashes—like this—which are not widely taught in high schools. Students used to use hyphens or en dashes – like this – but this year I'm seeing almost exclusively em dashes. (It’s always been a trick to save on word count, but their extensive use tends to support other evidence.)

4. Tricolons (especially ascending tricolons)

A tricolon is a rhetorical device involving three parts. I’m not going to go into detail about the history, but they’re particularly prevalent in literature from all around the world. Famous examples include:

• "veni, vidi, vici" (I came, I saw, I conquered)
• "Stop, drop, and roll"
• "life, liberty, and the pursuit of happiness"
• "truth, justice, and the American way,"
• "The Good, the Bad, and the Ugly."

Tricolons are especially prevalent in American political speech. Abraham Lincoln's Gettysburg Address,, John F. Kennedy's "we choose to go to the moon" speech, and Barack Obama's second inaugural address are replete with them. There are even “nested tricolons,” in which the third element of a tricolon is a tricolon itself.

Before ChatGPT, tricolons were common rhetorical devices in college admissions essays. I observed that some good writers would use them without even being conscious of it (a student of mine who got into Yale’s Eli Whitney non-traditional undergraduate program used them beautifully despite no formal writing education). But ChatGPT loves them. In particular, it makes extensive use of “ascending” tricolons, in which the three items are progressively longer, or the first two are an equal number of syllables and the third is greater. Most of the examples above ascending tricolons.

Here are some examples of how ChatGPT uses tricolons (I prompted it):

I honed my skills in research, collaboration, and problem-solving.

My love for literature grew from fascination to passion to purpose.

I have learned to persevere in the face of challenges, to embrace new opportunities, and to lead with empathy and conviction.

If I see one tricolon in an essay, I'm not usually suspicious. If I see four or five, I can be almost certain ChatGPT had a “hand” in it. If you used ChatGPT to help with your essays, how many tricolons can you spot?

5. “I [verb]ed that the true meaning of X is not only Y, it's also Z”

This is a college essay cliché that ChatGPT takes up to 11. I see this a lot. Here are some examples:

I learned that the true meaning of leadership is not only about guiding others—it's also about listening and learning from them.

I realized that genuine success is not just about achieving personal goals, but contributing to the well-being of humanity.

I came to appreciate that the core of resilience is not only enduring hardship; it's also finding strength through vulnerability.

Comment if you just re-read your essays and cringed!

6. “As I [synonym for advance in my education], I will [synonym for carry or incorporate] this [lesson or value]”

This is a common conclusion ChatGPT uses. Again, on its own it might not be a red flag, but it provides circumstantial evidence. Examples:

As I progress in my academic journey, I will continue to integrate these principles into my work and life.

As I delve deeper into my field of study, I will strive to uphold the values of curiosity and integrity that shaped me.

As I grow as a learner and individual, I will ensure that this lesson guides my decisions and aspirations.

These aren’t quotes from actual students’ essays, but I’ve seen a lot of this stuff lately.

7. “Lord of the Rings” syndrome (multiple endings)

One famous criticism of the Lord of the Rings films, in particular the third movie Return of the King, is that they have multiple scenes (as many as six depending on the version) that could stand alone as endings.

If not prompted otherwise, ChatGPT writes very formulaic and clichéd endings (and will suggest the same for revisions). It also tends to write multiple endings. I find that ChatGPT’s writing is more often than not improved by deleting the final sentence or paragraph. People do this too, especially when trying to pad word count, but it’s a reflection of what ChatGPT “thinks” a good essay looks like based on thousands of examples.

Often, these multiple endings include clichés 2, 3, and/or 4 above. If one of the essay’s possible endings is about the true meaning of something, or an explicit look to the future, and/or contains an em dash—then I know it was probably ChatGPT.

What this means

One of the students whose essays I reviewed admitted he used ChatGPT, but he wasn't worried because he ran it through several AI detectors, and they came up with low percentages. Yet I could tell right away, and I’d bet most admissions officers could as well

I don't claim to be better than any particular AI detector, but I do caution students (and universities) about relying on them. Reading is an intuitive process, and admissions officers (as well as professional counselors) have a large dataset of their own they’ve trained on, in particular essays from students of similar backgrounds. ChatGPT’s dataset likely doesn’t have a lot of demographic data about the authors of particular essays it's trained on.

College admissions essays have never been a great test of writing ability. Admissions offices encourage students to get feedback from others, and spelling and grammar-check software has been around a long time. There are also professionals who help students brainstorm, outline, revise, and polish their essays, and may have a “heavy hand” in the process. Then there are other less scrupulous people who will straight out write essays for applicants. But colleges have never taken significant measures to mitigate this. They could, with proctored writing tests and such, but they’ve never really cared enough. I find it curious that it’s only now that ChatGPT is accessible to everyone—not just privileged families—that some colleges seem to care.

At some point I'll probably write a post about how applicants should use ChatGPT, but this post should illuminate what you shouldn’t let it do: write or rewrite large sections of your essays.

As an aside, in the past two years, ChatGPT has made me a better writer. And it's not because I have it provide feedback on my social media posts and communications, but because I challenge myself to write better than ChatGPT. It’s one of the most astounding inventions in the history of the world, but it's still limited. GPTs rely heavily on what is. Creative writing—and art in general—is about expanding the realm of what might be.

And no, I did not use AI to write that.

Addendum: When I asked ChatGPT to evaluate my post up to this point, it told me to “tie your observations back to the importance of originality in writing and provide actionable advice for students,” and—I kid you not—suggested the following conclusion unprompted:

"The ability to recognize ChatGPT’s writing patterns is increasingly important, not only for admissions officers but for students striving to produce authentic and compelling essays. While AI is a powerful tool, true creativity lies in pushing beyond what it predicts to explore new possibilities. Writing is about more than filling a page—it’s about telling a story that only you can tell."

When I pointed out that this suggestion used four of the seven clichés I listed, it came up with this version:

Recognizing ChatGPT’s patterns helps us understand both its strengths and its limitations as a writing tool. While AI-generated essays may appear polished, they often lack the originality and context that make human writing resonate. For students, this is a reminder to focus on authenticity and individuality. After all, the most compelling essays are not those that follow formulas, but those that reflect a writer’s unique voice and perspective.

When I pushed it to eliminate clichés, it doubled down and introduced others:

ChatGPT is a mirror, reflecting back what it’s been taught, polished and predictable. The best essays, however, aren't mirrors—they're windows, revealing something unexpected, personal, and alive. If the goal is to stand out, the strategy is simple: write something no AI could ever predict, because only you lived it.

After I tried to prompt it not use my clichés, it came back with a tricolon (descending this time), an em dash, a version of “X is not about Y, it's about Z,” and an extended metaphor about mirrors and windows!

ChatGPT isn’t wrong, and this is not bad writing. But this is the “voice” of ChatGPT.

I think I've found a limit.