Write Clear Text and Messages 569

Step 8: Write Clear Text and Messages 569

words in length cause a loss in reading comprehension with each additional sen- tence word. It is also recommended that the number of sentences in a paragraph should not exceed six. Another research study created messages at three levels of reading ability (fifth-, tenth-, and fifteenth-grade) and tested them on people of varying verbal abilities. The fifth-grade version was found to be best for all lev- els. People of high verbal ability did not perceive the fifth-grade version as insult- ing, as some had feared. So, break long sentences into two or more simple sentences if this can be done without changing the meaning. Always write at the eighth grade level or less for the general population.

Directly and immediately usable. Searching through reference material to translate

a message is unacceptable, as are requirements for transposing, computing, inter- polating, or mentally translating messages into other units.

Affirmative statement. Affirmative statements are easier to understand than nega- tive statements. For example, “Complete entry before returning to menu” is eas- ier to grasp than “Do not return to menu before completing entry.” Tell a person what to do rather than what to avoid. There is an exception, of course. The user may be told how to avoid a situation with disastrous consequences.

Active voice. Provide simple and direct language. The active voice is easier to understand and usually more concise than passive voice. For example, “Send the message by pressing TRANSMIT” is more understandable than “The message is sent by pressing TRANSMIT.”

Temporal sequence . If a sentence describes a temporal sequence of events, the order of words should correspond to this sequence. A prompt should say, “Complete address and page forward” rather than “Page forward after complet- ing address.”

Main topic at beginning. Information that must be remembered should be placed at the beginning of a message or sentence. A person can remember something longer if it appears at the start. Items in the middle of a sentence or message are hardest to remember.

Parallel construction. Use the same grammatical structure for elements of sentences or messages that provide the same kind of information. For example, say “Use this control to select one choice” and “Use this menu to select one option,” not, “To select one choice use this control,” and “This menu is used to select one option.”

Nonauthoritarian. Imply that the system is awaiting the user’s direction, not that the system is directing the user. For example, phrase a message as “Ready for the next command,” not “Enter the next command.”

Nonthreatening. Negative tones or actions, or threats, are not very friendly. Because errors are often the result of a failure to understand, mistakes, or trial- and-error behavior, the user may feel confused, inadequate, or anxious. Blaming the user for problems can heighten anxiety, making error correction more diffi- cult and increasing the chance of more errors. Therefore, harsh words like “ille- gal,” “bad,” or “fatal” should be avoided.

Also, avoid using the word “error” in messages when it implies a user error.

570 Part 2: The User Interface Design Process

problem. For example, instead of saying “Error — Numbers are illegal,” say “Months must be entered by name.” Because the computer does not have an ego to be bruised, an excellent design approach would be to have it assume the blame for all miscommunications.

Nonanthropomorphic. Having the computer “talk” like a person should be avoided for several reasons. First, an attribution of knowledge or intelligence implies a much higher level of computer “knowledge” than actually exists, creat- ing shattered user expectations. Second, this attribute eliminates the distinction that actually exists between people and computers. People “control” computers; they “respect the desires” of other human beings. Third, many people express anxiety about using computers by saying things like “They make you feel dumb.” The feeling of interacting with another person who is evaluating your proficiency can heighten this anxiety. There is also some research evidence that a nonanthropomorphic approach is best, being seen as more honest, preferred, and easier to use.

The best advice at this moment is do not give a human personality to a machine. Imply that the system is awaiting the user’s direction, not vice versa. Say, for example, “What do you need?” not “How can I help you?”

Nonpatronizing. Patronizing messages can be embarrassing. “Very good, you did it right” may thrill a fourth grader, but would be somewhat less than thrilling to an adult. Being told “You forgot again” once may be acceptable, but being told three or four times in one minute is another story. In a commonly available video golf game, after a player makes a high score on a golf hole, the program returns with the suggestion to the player to “Try another sport.” A golf professional that played this game took great offense to this advice and walked away. Would Tiger Woods appreciate this kind of suggestion? A person may disagree with patroniz- ing conclusions, so why risk the offense?

Punishment and humor. Until an optimal computer personality is developed, mes- sages should remain factual and informative, and should not attempt humor or punishment. Humor is a transitory and changeable thing. What is funny today may not be funny tomorrow, and what is funny to some may not be to others. Punishment is never a desirable way to force a change in behavior, especially among adults.