Publishers often urge authors to make their books and articles "readable," but what does that mean? If you write books intended for children, obviously you need to adapt your writing to the reading skills and background young people are likely to have at the targeted age levels. Or, if your purpose is to explain medical treatments to patients and caregivers, the information must be couched in especially clear sentences and nontechnical language. Even if your book is intended for high school or college students, many of today's students haven't developed mature reading strategies. Adults, too, in this age of movies and television, may have allowed their reading skills to grow rusty. It's quite a challenge to make information accessible to readers whose abilities vary widely yet not produce a "dumbed down" book. Readability formulas can help by providing rough guidelines, but they are no substitute for professional judgment. You can also adjust your style so that readers can grasp the content more readily, a strategy that will work to your advantage as well as the reader's. Technology offers some assistance, but not as much as computer programs seem to promise.

Defining Readability. What makes a book or printed material "readable"? For educators, the term readability means a level of reading difficulty that corresponds roughly to the grade level at which young people would probably understand it. For pamphleteers, readability takes into account visual aspects such as attractive graphics, colors, and white space. For editors, it can mean the pleasure readers get from well-crafted prose, including such subtleties of style as word choice, sentence variety, rhythm, tone and figurative language. In practice, of course, these qualities overlap.

Several formulas for readability have been developed to give authors and publishers a general idea of reading difficulty according to a hypothetical grade level. These formulas are based upon the assumption that monosyllabic words and short sentences are easier to read than polysyllabic words and complicated sentence structure. Obviously these purely mechanical measurements must be interpreted with caution, since a short word like "vile" can be less familiar to a young reader than a longer one like "television."

A readability formula cannot analyze subtleties such as figurative language, symbolism, or connotations. Nor can it measure the quality of the thoughts expressed. However, it can make some generally useful comparisons if its limitations are taken into account. In writing for children or adults of limited reading proficiency, you can keep the information accessible by using short, concise, clear sentences. Choosing interesting verbs and specific nouns will keep your style from seeming childlike, even in short sentences. Readability formulas can speed up your calculations, but professional judgment and common sense should override any mechanical analysis. Your editor's advice and knowledge of your book's target audience should also carry weight.

Uses and Misuses of Technology. Computers have simplified the tasks of word-counting, sentence-counting, and calculation that formerly daunted our efforts to determine reading levels. The popular software Grammatik, for example, analyzes "statistics" in a given article, including an estimated readability level. Here's how it works. While you have on your computer screen the document you want analyzed, open Grammatik, select "View" from the top line of the opening box, then "Statistics" from the pull-down menu. A box appears telling you the number of words and sentences in your document, the average sentence length, and the number of "big words." If you click on the "Readability" box in the lower left corner, Grammatik applies the Flesch-Kincaid formula to estimate the reading level. According to that formula, a Hemingway short story registers approximately fourth grade level and Lincoln's Gettysburg Address above the twelfth grade level.

Other software programs that measure readability are available for $100 or less, but I have not personally used them. You might want to check out the program Readability Calculations, which analyzes a document using nine different readability formulas, Readability Analysis, which uses three formulas, and RightWriter, which analyzes grammar, style, and usage as well as assigning readability levels. RightWriter also allows users to select settings for general or technical writing, manuals, or proposals. (See notes in right column.)

A word of warning about grammar checkers: If you know enough about grammar to make good use of them, you don't need them. My grammar checker once scanned a line of prose reading "She looked so sad" and flagged it as an error with this comment: "The verb _looked_ does not usually take an object." Apparently Grammatik cannot recognize a linking verb and its predicate adjective. Besides, sometimes _looked_ is an action verb that can take an object. What if I had written "She looked daggers at him"? At this stage of development, style and grammar checkers should be used only with great caution. Word-counting tools, however, are useful to estimate the length of a column or story.

Stylistic Improvements. If you tend to overuse sentences starting with "there" and passive voice constructions, style-checkers can flag these to help you judge whether or not to rewrite some sentences. Yet again, your judgment must prevail, because sometimes the passive voice serves your purpose better than active voice. Note that neither of these stylistic flaws can actually be called mistakes. The overuse of such constructions, however, will weaken your prose style. Here's why. In spoken English, we often use the expletive "there" at the beginning of a sentence to signal that the true subject, often a lengthy one, will come after the verb. The expletive acts as a "place holder" that signals the hearer to wait for the subject. Written English, however, can be comprehended more quickly than spoken English (the eye works faster than the ear). Unnecessary expletives make written sentences seem wordy. Another reason for caution involves verb choice. The expletive "there" is followed by some form of weak "be" verb, usually "is" or "are." Verbs that suggest some action or image make your style livelier. Also, because the true subject comes after the verb, the use of an expletive often leads to errors in subject-verb agreement. The sentence below can be improved by eliminating the expletive:

Weak use of the expletive "there":
There are 46 chromosomes in a human cell.

Improved (more concise, better verb):
A human cell contains 46 chromosomes.

The same logic applies to the passive voice. As the name implies, the subject of a sentence in the passive voice is passive -- it receives some action by someone or something else (for example: "The Crucible" was written by Arthur Miller during an era of persecution and blacklisting). Sentences in the active voice show the subject performing the action (Arthur Miller wrote "The Crucible" during an era of persecution and blacklisting). Active voice is generally preferred because it shows more vigor, and it is more concise. Here is an example:

Weak use of passive voice:
Death rates for children worldwide have been reduced by immunization programs.

Improved with active voice:
Immunization programs have reduced death rates for children worldwide.

In the example above, the active voice makes the sentence more forceful and more concise. Also, placing the immunization programs in the subject position emphasizes the programs rather than the death rates.

Yet passive voice may be preferable in instances such as these:

• When the receiver of the action is more important than the doer, as in "Her three sons were killed in the Vietnam War."
  
  
• When the doer is unknown or uncertain, as in "During the 1930's, many small businessmen were forced to close their doors."
  
  
• When the subject is a passive participant, as in "The murder victim had been stabbed repeatedly."
  
  
• When you wish to keep the writer in the background, placing emphasis upon the action, as in, "The meeting was conducted during evening hours so that more citizens could attend."

One more recommendation to test how readable your prose is: Read your drafts aloud, and if your tongue gets tangled or the rhythms sound awkward, revise.