The phrase "a study that I" is correct and usable in written English.
It can be used when referring to a specific study that the speaker is involved in or has conducted.
Example: "I recently completed a study that I believe will contribute significantly to our understanding of climate change."
Alternatives: "a research project that I" or "an analysis that I".
In a study that I conducted with two colleagues, we analyzed the impacts of high-quality elementary school teachers on their students' outcomes as adults.
In a study that I conducted, Women Create a Sustainable Future, I investigated the correlation between having even one women on a board and improved ESG performance among 1200 Fortune companies.
Preliminary results of a study that I conducted with Steve Sexton and JunJie Wu suggest that the drastic increase in energy prices around 2007 and 2008 were major contributors to the widespread home foreclosures in California and the financial crisis.
The conclusion that I reached from my empirical work on marine parasites was corroborated by a study that I led to synthesize how biodiversity loss mediates the risk of zoonotic disease for human populations (6).
I recall a study that I conducted years ago involving a global analysis of some oceanographic features that I was modeling to understand the rheology of oceanic plates on million-year time scales.
A concerning finding emerged from a study that I read recently.
The first letter "was fabricated to help collect data for a research study that I designed concerning vendor response to consumer complaints," Professor Flynn explained.
In a Lego swallowing study that I wrote about previously for Forbes, the FART (Found and Retrieved Time) score for five Lego-swallowing adults volunteers ranged from a little over one day to about three days.
I had a routine of study that I followed meticulously for the stage or interview.
It's an interesting case study that I spoke about earlier today as part of my presentation at the "new new internet" conference in Washington DC.
"It's such a special study that I'm fairly confident that cannabis is safe for over-18 brains, but risky for under-18 brains".
