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Since I tried Ludwig back in 2017, I have been constantly using it in both editing and translation. Ever since, I suggest it to my translators at ProSciEditing.

Justyna Jupowicz-Kozak
CEO of Professional Science Editing for Scientists @ prosciediting.com
I couldn't determine
Grammar usage guide and real-world examplesAlternative expressions(20)
I couldn't figure out
I wasn't sure
I was unsure whether
I couldn't understand
I failed to grasp
I was baffled by
I was stumped
I drew a blank
I was uncertain
I felt unsure
I had my doubts
I wasn't certain
I couldn't say for sure
I wasn't convinced
I questioned it
I lacked confidence
I wasn't confident
I didn't understand
I was uncertain if
I was doubtful whether
Table of contents
Usage summary
Human-verified examples
Expert writing tips
Linguistic context
Ludwig's wrap-up
Alternative expressions
FAQs
Human-verified examples from authoritative sources
Exact Expressions
7 human-written examples
After a single viewing, I couldn't determine Mr. Malick's attitude toward religious faith.
News & Media
Yet I couldn't determine where theoretical extremity ended and individual experience began.
News & Media
I couldn't determine the ingredients of their chicken nuggets (no one can, apparently) so I did my own version, using actual coal nuggets flavoured with bergamot and hydrochloric acid and it works really well.
News & Media
I couldn't determine if the writer of "Keep Your New Age Cyberjock, and Send Me a Handsome Handyman" (April 2) was motivated by lust or was indifferent to her lack of knowledge.
News & Media
Another commenter, now living in New York, describes her Cageian revelation while living in Cape Breton, Nova Scotia: I vividly remember for the first few days there was a sound that was driving me insane because it wouldn't stop and I couldn't determine its source.
News & Media
She alluded to using again; I couldn't determine if she meant she was or not.
News & Media
Human-verified similar examples from authoritative sources
Similar Expressions
47 human-written examples
At that moment, in my haze of vainglory, I could not determine a single personal deficit.
News & Media
I could not determine how Henrick fitted into the Icke camp.
News & Media
His eyes were alight with a strong emotion of some sort, but I could not determine which.
News & Media
For reasons I could not determine, Steven -- who would not give his last name, perhaps because of fire codes -- had affixed a lighted candle to the top of his bald head, like one of the singing incendiaries in "Beauty and the Beast".
News & Media
While this works in theory, and I was able to upload a zipped folder with multiple files, Fluxiom did not automatically unzip the folder and I could not determine a way to do it with the service.
News & Media
Expert writing Tips
Best practice
Use "I couldn't determine" to signal a professional boundary where evidence was insufficient to reach a conclusion. It is more objective than saying "I didn't know".
Common error
Do not use "I couldn't determine" when you actually mean "I couldn't decide". The word "determine" implies a search for an objective fact or truth, whereas "decide" refers to a personal choice or preference.
Source & Trust
93%
Authority and reliability
4.9/5
Expert rating
Real-world application tested
Linguistic Context
This phrase functions as a declarative statement utilizing the modal verb "could" in its negative past form to express a lack of ability or success. According to Ludwig, it serves to report the result of an inquiry where no definitive answer was found.
Frequent in
News & Media
55%
Science
30%
Formal & Business
15%
Less common in
Social Media
5%
Informal Speech
10%
Encyclopedias
5%
Ludwig's WRAP-UP
The phrase "I couldn't determine" is a powerful tool for writers who need to express a lack of certainty without sounding uninformed. Ludwig AI shows that this expression is highly prevalent in investigative journalism and scientific research, where it acts as a marker of methodological rigor. By stating that you "couldn't determine" something, you imply that an effort was made, but the available data did not support a clear conclusion. While "I could not determine" is preferred for purely academic contexts, the contracted form is the standard for high-quality news and professional reports.
More alternative expressions(10)
Phrases that express similar concepts, ordered by semantic similarity:
I was unable to determine
More formal by replacing the contraction and modal with a state-of-being construction.
I could not determine
Removes the contraction for a more formal or academic tone.
I couldn't ascertain
Uses more sophisticated vocabulary, often implying a formal investigation or verification process.
I couldn't figure out
A more informal, conversational phrasal verb synonymous with solving a puzzle or understanding.
I wasn't able to tell
Uses simpler language, often used when referring to visual or sensory perception.
I couldn't identify
Specific to the act of recognizing or naming a particular thing or person.
I failed to establish
Stronger emphasis on the lack of success in reaching a definitive conclusion.
I couldn't verify
Specifically relates to confirming the truth or accuracy of something.
I couldn't conclude
Focuses on the final step of the reasoning process rather than the discovery itself.
I was unsure whether
Softens the statement by focusing on the speaker's state of mind rather than the action of determining.
FAQs
How do I use "I couldn't determine" in a sentence?
You can use it to describe a failed attempt to find information, such as: "After reviewing the data, "I couldn't determine" the exact cause of the system failure."
Is it better to use "I couldn't determine" or "I could not determine"?
In formal writing or academic papers, use "I could not determine". In journalism or professional emails, the contraction "I couldn't determine" is perfectly acceptable.
What is a more informal way to say "I couldn't determine"?
A common informal alternative is "I couldn't figure out" or simply "I wasn't sure".
When should I use "ascertain" instead of "determine"?
Use "I couldn't ascertain" when you want to emphasize the difficulty of getting definite information in a very formal context.
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Table of contents
Usage summary
Human-verified examples
Expert writing tips
Linguistic context
Ludwig's wrap-up
Alternative expressions
FAQs
Source & Trust
93%
Authority and reliability
4.9/5
Expert rating
Real-world application tested