Quantity words, such as “less” and “fewer,” are used to add information about the number or amount of the noun. However, how do you know which one to choose? The first step is to look at the noun being modified and to determine if that noun is countable (the noun can be made plural, often by adding -s or -es) or uncountable (the singular and the plural forms of the noun are the same).
“Fewer” can be used with plural, countable nouns, such as “studies,” “limitations,” and “factors”
“Less” can be used with plural uncountable nouns, such as “research,” “evidence,” and “information”
For more information, see the webpage on count and noncount nouns. Of course, actual usage from this prescriptive rule may vary a bit. You can look up the uses of “less” and “fewer” in the Corpus of Contemporary American English for some examples. This SMRTguide on Using a Corpus to Revise for Grammar and Scholarly Voice shows a couple of examples of how you could use the corpus.
Revision Tip: Do a search for the words “less” and “fewer” in your latest draft of your doctoral capstone manuscript. Then, take a look at the noun after the words “less” and “fewer.” Is it a plural, countable noun? If so, did you use the word “fewer”? Is it a plural uncountable noun? If so, did you use the word “less”? Revise as needed. Happy Writing!