Usage tip: fewer vs. less and other comparison words

In my last tip, I discussed when to use amount vs. number. Two other commonly confused words, fewer and less, are frequently misused for the same reason as amount/number. The good news: They follow basically the same rule. Learn it once and solve both problems!

Fewer is used to compare concrete nouns, the same words that would be counted with the word number. Less is used to compare abstract nouns, the same words that would be quantified (but not directly counted) with the word amount.

• The event drew fewer participants this year than last year. ["Participants" are individuals that can be counted.]
• Phil loves his new job even though it offers less opportunity for advancement than his former field did. ["Opportunity," in this sense, is an abstract idea.]

As is the case with amount/number, the correct use of comparison words changes when a sentence is revised to include or exclude phrases that modify abstract terms:

• As the day grew hotter, the protesters' speech became less insulting. ["Speech" is abstract.]
• While still angry, the protesters spewed fewer venomous insults as they tired in the midday heat. ["Insults" is concrete.]

If you find the concrete/abstract concept confusing, don't lose heart or patience. Perhaps you can simply avoid the question of which term is correct by revising your sentence to show the opposite relationship. Note that fewer and less reflect a decreasing quantity. At least two comparison words that reflect an increasing quantity require no special handling. 

• more
• "We hold in our hearts more love than hate because we believe!" shouted the pastor, spurring a frenzied chorus of "Amens!" from the enthusiastic congregation. ["Love" is abstract.]
• Janet finally concluded there were more practical reasons to stay on the West Coast than to move to New England. ["Reasons" is concrete.]
• greater
• The seating capacity of Conference Room B is greater than that of Conference Room A. ["Capacity" is abstract idea.]
• Today, it's common to have a far greater number of highly qualified applicants than available jobs--in some cases, exponentially more than ten years ago. ["Number" is concrete.]

Readers, share your ideas. Do you have a handy memory tip that helps you decide when it's appropriate to use fewer vs. less? What other comparison words present usage problems? Let's discuss it in the Comments section.