It is obvious that both fewer and lesser are real words. It is the improper use of the two that we want to discuss. For discussion we will use few and fewer, and less and lesser to be grammatically correct.
Everyday on news broadcasts we see these two words used interchangeably by show hosts and guests as if they are the same words, but they are not. We also see this confusion by people with advanced degrees, just not advanced degrees in English. So let us examine some examples of this confusion.
Fewer refers to a count, a number that is smaller than some other number. It is used in conjunction with countable nouns, such as cars, bicycles, people, chairs.
“Two hundred people attended the show and that was fewer than expected.”
“I have fewer friends in the new subdivision we moved to but expect to make more soon.”
“There are fewer ice cream cones in the box than I counted yesterday.”
“Women commit fewer crimes than men.”
“In 1790 the United States had fewer than five million citizens.”
Lesser refers to a degree, a comparison between two or more things. It is used in conjunction with uncountable nouns, sometimes with abstract nouns such as light, beauty, or opinions.
“A high school teacher makes less money than a college professor.”
“The moon gives off less light than the sun.”
“He is paid much less than he really earns.”
“He was feeling less pressure in the new job than in the old one.”
“A rock is less buoyant than a stick.”
Once you know the difference you start to cringe when you watch the news. You can feel the error as it happens, and it becomes embarrassing for the spokesperson. If you want to instantly recognize the error, just reverse a few of these simple sentences above.
“There are less ice cream cones in the box than I counted yesterday.”
“Women commit less crimes than men.”
“The moon gives off fewer light than the sun.”
“A high school teacher makes fewer money than a college professor.”