Eliminating Sporadic Noise in Writing: A Style Guide for EE 333T

© Dr. David F. Beer, 1996

Table of Contents

Problems that crop up intermittently in writing, often referred to as "faulty mechanics" by English teachers, might be thought of as sporadic or intermittent noise. It tends to occur occasionally, rather than affect every page the way a poor choice of type size or confused organization of material might. Of course enough sporadic noise in a document, such as repeated misspellings or numerous sentence fragments, can easily turn into constant noise and give your reader an impression of hastily and carelessly produced work undeserving of the response or feedback you want.

To help you eliminate sporadic noise this guide looks at where it is most likely to occur in spelling, punctuation, sentence structure, and technical usage. We also give some pointers on how to edit your writing in order to remove this kind of noise.


You might think the spell checkers that come with most word processing software have eliminated any need to be a careful speller. Unfortunately this is not the case. With apologies to Shakespeare we took his words "A rose by any other name would smell as sweet," and ran them through a spell checker as A nose by any outer dame wood small as sweat. No red flags were raised by the program. Nor will spell checkers catch common errors such as confusing there for their, or to for too. Some typographical errors simple give you other words which will pass unnoticed, as in this sentence. A very slight slip of the finger on the keyboard can make the difference between asking for some forms to be mailed to you or nailed to you. A quick transposition could render a memorandum nuclear rather than simply unclear.

At best, the effect of poor spelling on your readers is a sense of annoyance, or at least of having their attention distracted by something other than what you want to communicate. At worst, noise created by spelling glitches can bring readers to a stop and cause them to seriously question your ability as a writer. They might even suspect that a person who is careless with spelling could also be inept in more critical technical matters.

To reduce or eliminate any noise in your writing caused by incorrect spelling, use a spell checker but also have a standard dictionary nearby. A current dictionary is the only resource that can reliably answer questions such as

It is especially important for an engineer to use a current dictionary. English is a dynamic language, and the language of science and technology changes even more rapidly as knowledge increases and devices are developed. You won't find words like software, modem, and LED in a dictionary from the 1950s, and since then older words such as bug, hardware, interface, and even mouse have taken on new meanings. Some usage has yet to be decided on: Would a computer shop advertise that it repairs mice or mouses? Do you send e-mail, E-mail, or email? (Right now all three options are used.)


Would you want to drive on a busy highway or in a city where there were no traffic signs? Controlling the flow of traffic is vital if anyone is to get anywhere. Similarly, within sentences the flow of meaning is controlled by punctuation marks, the conventionally agreed-upon "traffic signals" of written communication. We do the same thing in spoken language by means of pitch, breath pauses, and emphasis. Directing the flow of ideas in writing is not really difficult, and a useful procedure when you're unsure of how to punctuate a sentence might be to say it aloud as in normal conversation. Pay careful attention to where you pause naturally within the sentence-that is likely to be where you need some punctuation.

Many detailed guides to punctuation exist, and you may want to look at them if you have a lot of queries in this area. You will also find excellent advice on punctuation in the front or back sections of some standard college dictionaries. Meanwhile, the following suggestions are offered on the most common problems many engineers tend to have with punctuation.


Confusion sometimes exists about commas because frequently their use is optional. Before we arrived at the meeting we had already decided how to vote would be written with a comma after meeting by some and not by others. The question to ask is, Does adding or omitting a comma in a given sentence create noise? In general, if no possible confusion or strain results, the tendency in technical writing is to omit unessential commas.

Often, omitting a comma after introductory words or phrases in a sentence will cause your reader to be momentarily confused-as you would have been if there were no comma after the first word of this sentence. Here are further examples of missing commas causing noise:


Again, try saying these sentences aloud with their intended meaning. You'll find you put the comma-or pause-where it belongs almost without thinking.

One more point about commas: most technical editors prefer what is called a "serial comma" when you list words or ideas within a sentence, as in The serial comma has become practically mandatory in most scientific, technical, and legal writing. You may have been told that the and joining the last two terms replaces the need for a comma, but this is not so in technical writing. See how the serial comma is useful in the following sentences by reading them aloud and noting how you need the pause before the and:

A serial comma may also prevent confusion:

Unless Johnson and Turblex is the name of one company, you will need a serial comma:


Parentheses are used to set off facts or references in your writing-almost like a quick interjection in speech:

If what you place within parentheses is not a complete sentence, put any required comma or period outside the parentheses:

If your parenthetical material forms a complete sentence, put the period inside the marks:

Remember, it is best not to use parenthetical material too frequently since these marks force your readers to pause, and are likely to distract them (if only for a brief moment-see what we mean?) from the main intent of your writing.


A dash will make a sentence seem more emphatic by calling attention to the words set aside or after it: He was tall, handsome, rich-and stupid. Since the dash is considered less formal than the other parenthetical punctuation marks (parentheses and commas), you should try to avoid it in very formal writing. If you overuse it, you are in danger of calling wolf too often, and your dashes will lose their effect. With this caution in mind, you may still find dashes helpful for the following purposes:




Notice we are talking about what is called the "em" dash here-the dash used between words that practically touches the letters at each end of it. The "en" dash is shorter, more like a hyphen, and used when you cite ranges of numbers: 31-34; $350-400. Most word processing programs allow you to choose whichever you need.


Colons are used to separate the hour and minute in a time notation and to divide parts of the title of a book or article:

The most common use of the colon within a sentence, however, is to introduce an informal list:

You can also use a colon to introduce an illustration or example, as we did in the sentence leading into the above example. Note, however, that in both cases an independent clause-a statement that can stand by itself and have meaning-comes before the colon. You should not write the example sentence as

because what comes before the colon makes no sense by itself and a colon needlessly interrupts the flow of the sentence. Instead write

(Note how the same reasoning made us lead into the last two illustrations with no colon after the words ". . . example sentence as" and "Instead write. . . .")


Hyphens have been called the most under-used punctuation marks in technical writing. Omitting them can sometimes create real noise, as when we read coop (an enclosure for poultry or rabbits) but discover that co-op was meant. On the other hand, a hyphen sometimes appears where it is unneeded, as in re-design or sub-question.

Unfortunately, apart from the general rule that hyphens should be used to divide a word at the end of a line or to join pairs of words acting as a single descriptor-as in The transistor is a twentieth-century invention-there is no clear consensus on when to use them. You'll often have to decide for yourself with the help of a recent dictionary, but here are some suggestions:

With really complex technical terms you may have very little to go on regarding hyphens. For instance, how do you punctuate direct axis transient open circuit time constant? The best solution (direct-axis transient open-circuit time constant) may only be found in a technical dictionary or by observing what the common practice is among specialists in the field.

Exclamation Point

The best advice on the exclamation point is to use it all you want in your novel or letters, but avoid it in professional writing except in the case of warnings (DANGER: Sodium Cyanide is extremely toxic!). Since engineering documents seek to convey information, any excitement or triumph should be generated by the facts provided in the document rather than by a tagged-on marker. Occasionally an exclamation mark might even be interpreted by your readers as condescending or sarcastic:

Quotation Marks

Use quotation marks to set off direct quotations in your text, and put any needed period or comma within them, even if the quoted item is only one word. Although British publishers use different guidelines, the American practice is to always put commas and periods inside quotes, and semicolons and colons outside, as in the following:

If you have to quote material that takes up more than two lines, set it off from your text by a space and indent it from both right and left margins. You might even use a slightly smaller font size, and should omit the quotation marks, as shown here:


Whether we like it or not, the semicolon seems to be disappearing from much engineering writing. Often it is replaced by a comma, which is an error according to traditional punctuation rules. More frequently we simply use a period and start a new sentence, but then a psychological closeness might be lost. Look at these two examples:

The relationship between these statements could be better stressed by using a semicolon:

Perhaps one reason we don't see many semicolons in engineering writing is that fewer and fewer people feel confident using them. Another possibility is that little noise results from using a comma or a period and new sentence, as in the examples above. Note this pair of sentences:

Although the first sentence would be considered correct and the second wrong, you will find plenty of examples of the second punctuation around. The main problem in the second sentence is that a reader can't be sure at first whether however "belongs" to the first half of the sentence or the second. A semicolon after yesterday is really needed to make this clear. If you frequently use words like however, therefore, namely, consequently, and accordingly to link what could otherwise be two sentences, insert a semicolon before and a comma after them. You'll find this will add a shade of meaning that cannot be achieved otherwise.

Use semicolons to separate a series of short statements listed in a sentence if any one of the statements contains internal punctuation. The semicolon will then divide the larger elements:


As engineering writers our aim is to convey information with a minimum of noise. For our purposes the only important "rule" of grammar is to eliminate noise so that the decoder (reader) of the text (message) receives precisely the message the encoder (writer) intends. Thus it's worth looking at those grammatical and stylistic areas where noise often seems to occur in engineering writing. Two persistent but outmoded grammar rules you can safely forget are also discussed in this section under the heading of "Some Latin Legacies."

Connecting Subjects to Verbs

It's unlikely you would write The machines is broken without quickly noticing a discrepancy between the subject (machines) and the verb (is). A problem can occur, however, when several words come between your subject and verb and you forget how you started the sentence. If you are writing in a hurry and leave no time for editing, you might produce something like this:

Those plural nouns that follow later (components, buildings, structures) can sometimes mislead us into relating the verb to them rather than to the earlier nouns (combination, film, one) to which they belong. This danger increases with the length of a sentence and the amount of information intervening between the true subject and verb of a sentence. A good style or grammar program on your word processor may help prevent this from happening, but it is just as well to be alert to the danger.

Sometimes a question arises in engineering writing with units of measurement. Do you write Twelve ounces of adhesive were added or Twelve ounces of adhesive was added? How about 12 grams of acid was spilled or 12 grams of acid were spilled?

The answer is a matter of logic rather than grammar. Even though we're alluding to several ounces or grams here, we "see" them as one unit, and thus the singular verb is preferable. Little or no noise is created, however, if you slip up on this one.

Using either/or in a sentence occasionally makes us stop and think. Look at this sentence:

Which verb should we use? Since a verb is normally controlled by the noun immediately before it, we would write Either the old manual or the recent procedures are acceptable. Following this practice we could also write

It is best to follow the same rule with neither/nor. Thus the following two sentences would be preferred:


A modifier is a word or group of words whose function is to add meaning to other ideas in a sentence. If you say your company has bought a transceiver, you have certainly conveyed some meaning, but if you say Our company has bought a TS 840 S transceiver with single sideband capabilities, you add a lot of meaning to the word transceiver by adding some modifiers.

The danger lies in creating noise by misplacing the modifiers in a sentence. Such distortion can produce sentences that don't make sense or that make sense in the wrong way. Misplaced modifiers occur when a reader gets the wrong impression (or no impression) of who is doing what in a sentence. This is frequently because words like "I" or "we " or "the engineers" or some other subject has been omitted. Consider the following:

If we look at these statements logically we have a horse that rides, a theory that can test a circuit, and equipment that modifies and adjusts. This is not likely to be what the writer meant. Revising the last two sentences might result in the following:

Meanwhile, another problem can crop up if you place a modifier too far from the word or idea it modifies:

It's not hard to remedy the lack of logic in these sentences and to avoid traveling by fax or having four year old fathers, but sometimes the meaning cannot be extracted, as in the following:

The sentence is correct if the telephone answering device is made of analog devices, but much more likely the writer is concerned with the inaccuracies of an analog tone-detector circuit. This is easily fixed:


Parallelism refers to the need for items in a list to share the same grammatical structure. Faulty parallelism creates noise because it violates a sense of logical consistency. Rather than tell someone you like to jog, wrestling, and play the fiddle, you would probably say you like to jog, wrestle, and play the fiddle, or that you enjoy jogging, wrestling, and playing the fiddle. But in longer sentences there is a danger of losing control of this logic.

Note how this sentence reads as if the team's alternatives are (1) to call in a consultant, and (2) having more engineers reassigned-two unparallel statements that can grate on our sense of logical flow. The sentence can be rewritten to state that the alternatives were to call in a consultant....or to have three more engineers reassigned. See if you can recognize the lack of parallelism in this sentence:

To make this statement parallel, think of the list embedded in it. We are told that the back-up system

To be consistent, the sentence needs one more should-or one less:

This might seem like a rather fine point, but since a lack of parallelism can often cause a reader to pause, if only subconsciously, it qualifies as noise when it occurs in a sentence.


Sentence fragments are partial statements that create noise because they convey an incomplete unit of information. Here is an example:

The first sentence makes sense by itself; try saying the second statement alone, as an independent exclamation, and your listeners would be lost. We must admit, however, that in everyday speech and popular journalism you will find plenty of fragments which seem to cause little or no noise. Look at this example:

We know what the writer means here, but strictly speaking the second statement is a fragment because it could not stand alone and make sense. The words In spite of indicate a contrastive relationship that is clear only in the context of the first statement. It would be more efficient to write

In your formal engineering writing you would do well to avoid incomplete sentences. They can usually be quite easily remedied, as you can see. Here's another example:




Active or Passive Voice?

As indicated in the last pair of sentences above, we can use two distinct 'voices' in English sentences. The active voice directly states that someone does something, as in The engineer wrote the report. The passive voice turns it around to The report was written by the engineer. Thus the active voice emphasizes the performer of the action-the engineer, in our example-while the passive emphasizes the recipient of the action, the report.

Many engineering and scientific writers in the past have been advised to leave themselves out of their writing. They might write It was ascertained that. . . long before they would admit We made sure that. . . . Chances are management would rather tell you It has been decided to terminate your employment than We have decided to fire you. Perhaps such hedging is necessary at times (it helps conceal responsibility), and there is something to be said for "scientific objectivity," but the natural form of the English sentence is the active voice. This form is also the more efficient one. Look at the following pairs:

The use of the passive becomes especially burdensome in procedures or instructions:

Fortunately modern engineering writers are getting away from the rigid use of the passive as they realize there is nothing dreadful about using the active voice. Sentences become more vigorous, direct, and efficient in the active form, and by showing that a person is involved in the work, you are doing no more than admitting reality. Also, the active voice gives credit where credit is due. If we read in a progress report that several references were checked out from the library and 25 pages of notes were taken, are we as impressed by the energy expended as when we read I checked out several books from the library and took 25 pages of notes?

One danger of avoiding the active voice is that we can end up writing some pretty absurd things:

Not every use of the passive is inadvisable, of course. Sometimes it will give variety to your writing, and passive verbs can always be used if the doer of an action is unknown or unimportant, or if what is being done is simply more important than the doer:

Perhaps the best policy is to use the active voice in your writing if it seems the most natural and efficient way to express yourself, assuming there is no company policy against its use (there is in some companies).

Sexist Language

Gender, or sex, is now only indicated in English by she /he, his /hers, her /him, and by a small group of words describing activities formerly pursued by one sex or the other, such as mailman, stewardess, chairman, or seamstress. Now of course men might bring the drinks on an airplane and women might deliver the mail, not to mention take an equal place in the engineering workplace. Because of this it is unnecessarily restrictive-and to some people offensive-to use gender-specific terms in writing and speech unless there is good reason to do so. The following pairs show how easy it is to reword your sentences or paragraphs to include everyone they should:







Most nouns indicating gender in English have already been modified to be inclusive. A recent dictionary can guide you here. One title that still sneaks through, however, especially in organizations traditionally dominated by males, is chairman. If the "chairman" is female, is she the chairwoman or chairperson? Both are acceptable, but it's probably simpler to refer to anyone in such a position as chair:

Some Latin Legacies

A few grammar rules impressed upon us in the past really do not hold up under careful linguistic or logical inspection. They were based on how Latin works, rather than English. To put it another way, noise rarely occurs when these rules are ignored. Here are the two main ones, together with comments and a caution.

1. "Never End a Sentence with a Preposition. "

In reality a preposition is often the best word to end a sentence with. (A purist might claim we should have just written . . . the best word with which to end a sentence ). When an editor criticized Sir Winston Churchill for doing so, Churchill responded with "Young man, this is the kind of nonsense up with which I will not put!" After all, did you find any noise in the opening sentence of this paragraph? Efficient writing sometimes dictates that we end a sentence with a preposition. Compare the following pairs. You can see that in each case the first sample, ending with a preposition, flows better and is more natural:

2. "Never Split an Infinitive. "

An infinitive is the form of a verb that combines with the word to, as in to go, to work, or to think. Confident writers have dared to deliberately split the infinitive whenever doing so was in the best interests of clear writing. Certain TV space adventurers have been daring to boldly go where the rest of us can't for a long time now, and an electrician may find it necessary (and safer) to entirely separate the wires in a power line sometimes. But don't overload a split infinitive. If you put too much material between your to and the rest of the verb, noise or even nonsense might result:

Rewrite this as


Transitional words and phrases are signposts that show a reader the way your thinking is going. They help connect ideas, distinguish conditions or exceptions, or point out new directions of thought. Simple words like therefore, thus, similarly, and unfortunately eliminate ambiguity by helping a reader interpret your information. So if you neglect transitions in your writing you create noise, since your reader might miss some important connection. Look at these two sentences:

Both sentences are grammatically correct and contain important facts, but can the reader tell how these facts are related? Now notice how the next three illustrations indicate relationships the first example does not:

While facts are important, it is often the relationships between the facts that create the whole picture. Thus you should make your transitions and connections as strong as possible. Here are some examples:

To indicate a sequence: before...later, first...second, in addition, additionally, then, next, finally

To indicate contrast: but, however, yet, still, nevertheless, although, on the contrary, in contrast, on the other hand

To indicate cause and effect: consequently, therefore, so, thus, hence

To indicate elaboration: further, furthermore, for example, moreover in fact, indeed, certainly, besides

Sentence Length

When dealing with highly technical subjects you should rarely write sentences over twenty words long. Technical material can be difficult enough to follow without being presented in long, complex sentences, particularly if your audience is less familiar with your field than you are. Even nontechnical ideas are hard to grasp in an unnecessarily longwinded sentence:

Nobody wants to be left breathless at the end of a mile-long sentence. If you find your sentences tend to be lengthy, look for ways to break them into two or more separate ones. The readability of your prose will be determined partly by the length of your sentences. On the other hand, too many short sentences may leave your readers feeling like first graders:

Try to vary your style and avoid both lengthy and abrupt sentences. Remember, however, that very short sentences, used sparingly, can be effective in helping you reinforce a point.


Useless Jargon

In its negative sense, jargon is pure noise since it refers to unintelligible speech or writing. The word derives from a French verb meaning the twittering of birds, and has a lot in common with "gobbledygook," first used to compare the speech of Washington politicians to the gobbling of Texas turkeys. High-tech jargon is sometimes known as techno-babble. Some people seem to like to sprinkle their writing liberally with such impressive-sounding phrases as integrated logistical programming, differential heterodyne emission, or functional cognitive parameters. Unfortunately, unless these words mean something to both writer and reader, no communication takes place.

Techno-babble is so common that we have created an "electrotechnophrase generator" to help addicts satisfy their habit. Select any three-digit number and read off the corresponding words from the chart below; for example we used 2-8-3 to get differential heterodyne emission. Readers may have no idea of what you mean, but they should be impressed-or afraid to ask for a meaning.

Column 1 Column 2 Column 3

0. voltaic integrated simulation

1. Sholokhov's semiconductor algorithm

2. differential Yagi attenuator

3. Fourier scaled emission

4. transient Q-factor diode

5. virtual tracking parameters

6. phasor diffusion network

7. compound Doppler gate

8. thermal heterodyne transducer

9. Gaussian coaxial magnetron

How To Sound Like A Real Technocrat

Useful Jargon

In another sense, however, jargon is the necessary technical terminology used in specialized fields. A chemist might use the term deoxyribose around a group of peers without feeling a need to explain it, just as a geologist could talk about the Paleozoic era or Devonian period with other geologists. Computer engineers can safely refer to bytes, bauds, and packet switching-among themselves. Communication between experts would be ponderous if not impossible if they had no specialized jargon. Moreover, each year technical language increases greatly as scientific knowledge increases; thousands of technical terms used today were unknown just a few years ago.

Sometimes you will find that common words take on new meanings when used by experts. Charge, conductor, mole, and mouse are just four examples. Printers (the people, not the machines) mean something quite different than most of us would when they refer to widows and leading. As engineers you know and use all sorts of technical jargon. Some you share with most engineers, some with those in the same general field of engineering as you-such as chemical, civil, or aerospace-and some you would use only among peers in highly specialized fields like celestial mechanics or software engineering.

There is only one way to avoid noise when using technical terminology: know your audience. Make certain you are writing or speaking at their level of comprehension, because if you're above their heads you will be wasting your time and theirs. Explain terms whenever necessary; don't risk confusing readers or losing them completely because they don't know what you are talking about. Definitions within your text, examples, analogies, or a good glossary are all useful tools for the technical writer who must frequently communicate with less technically inclined audiences.


Abbreviations are necessary in technical communication for the same reason valid technical jargon is: they refer to concepts that would take a great deal of time to spell out fully. It would be time-consuming and boring for a computer expert to read Computer-Aided Design/Computer-Aided Manufacturing several times (or hear it in a talk) when CAD/CAM would do. However, you will create a lot of noise in your writing if you use abbreviations your readers don't understand. Always spell abbreviations out the first time you use them unless you know this would insult the intelligence of your audience:

Once you have defined an abbreviation you can normally expect your reader to remember it. The exception to this would be if you are using some highly complicated or unusual abbreviations throughout your document, in which case you may need to remind readers more than once what the abbreviations stand for, or provide a glossary they can refer to.

Initialisms and acronyms

Abbreviations can be subdivided into initialisms and acronyms. Initialisms (sometimes called initializations) are formed by taking the first letters from each word of an expression and pronouncing them as initials: GPA, IBM, LED, UHF. Acronyms are also created from the first letters or sounds of several words, but are pronounced as words: AIDS, FORTRAN, NAFTA, NASA, RAM, ROM. Some acronyms become so well-known that they are thought of as ordinary words and written in lower case: bit, laser, pixel, radar, scuba, sonar.

Don't be surprised if you find a list of both initialisms and acronyms lumped under the title ACRONYMS. Many engineering writers no longer observe the distinction between the two, and call any abbreviation an acronym. You probably shouldn't make an issue of it, especially if the writer is your superior.

Two usage pointers:

1. Use the correct form of a/an before an initialism. No matter what the first letter is, if it is pronounced with an initial vowel sound (for example the letter M is pronounced "em") write an before it:

Some abbreviations might fool you. Consider LEM (lunar excursion module) for example. If the custom is to pronounce it as an initialism, L-E-M, then you will have an LEM. If it is normally considered an acronym (as one word), you will have a LEM.

2. Form the plural of acronyms and initializations by adding a lower-case s. Only put an apostrophe between the abbreviation and the s if you are indicating a possessive form:


Engineering means working with numbers a great deal. Frequently this is where a lot of written noise occurs due to typos, incorrect or inexact numbers, and inconsistencies. Obviously you can avoid serious noise by making certain any number you write is accurate. You should also give numbers to the necessary degree of precision: know whether 54.18543 is needed in your report or whether 54.2 will do. Avoid noise from inconsistent use of numbers by following these guidelines:

1. Numbers can be expressed as words (twelve) or numerals (12). Cardinal numbers are one, two, three, etc. Ordinal numbers are first, second, third, etc. Although custom varies, it's a good idea to write the cardinal numbers from one to ten as words and all other numbers as figures.

However, when more than one number appears in a sentence, write them all the same:

Also, use numerals rather than words when citing time, money, or measurements:

2. Spell out ordinal numbers only if they are single words. Write the rest as numerals plus the last two letters of the ordinal:

3. If a number begins a sentence, it's a good idea to spell it out regardless of any other rule.

To avoid writing out a large number at the beginning of a sentence, rewrite the sentence so it doesn't begin with a number:

NOTE: You may sometimes see very large numbers written with spaces where you usually put commas. Thus 10,354,978 might appear as 10 354 978. This is to avoid any possible confusion with the practice in some countries of using commas as decimal markers. Decide which method you want to use based on your company's preference and/or your audience.

4. Form the plural of a numeral by adding an s, with no apostrophe:

Make a written number plural by adding s, es, or by dropping the y and adding ies:

5. Place a zero before the decimal point for numbers less than one. Omit all trailing zeros unless they are needed to indicate precision.

6. Write fractions as numerals when they are joined by a whole number. Connect the whole number and the fraction by a hyphen:

7. Time can be written out when not followed by a.m. or p.m., but you will normally need to be more precise than this. Use numerals to express time in hours and minutes when followed by a.m. and p.m. or when recording data. Universal Time (UTC, from the French for universal coordinated time) uses the 24-hour clock.

8. When expressing very large or small numbers, use scientific notation. Some numbers are easily read when expressed in either standard or scientific form. Choose the best format and be consistent:

Units of Measurement

Although the public in the United States is still not committed to the metric system, you will find that in general the engineering profession is. Two versions of the metric system exist, but the more modern one, the SI (from French Système International), is preferred. The vital rule is to be consistent. Don't mix English and metric units unless you are forced to. Be sure to use the commonly accepted abbreviation or symbol for a unit if you do not write out the complete word, and leave a space between the numeral and the unit.

Many people, including technically trained ones, still think in standard or English units of measurement, so sometimes you may find it advisable to give both referents in your writing. As with many other editorial matters, you can only make this decision after thinking of your readers' needs. When it might be advisable to add "explanatory" units, as with a mixed audience, do so by writing them in parentheses after the primary units:

Make sure you use the correct symbol when referring to units of measurement, and remember that sometimes similar symbols can stand for more than one thing. A great deal of noise would result if you confused the following, for example:

Units of measurement derived from a person's name usually are not capitalized, even if the abbreviation for the unit is. Note also that although the name can take a plural form, an s is not added to the abbreviation to make it plural:

When working with very large or very small units of measurement you will need to be familiar with the designated SI expressions and prefixes:

A recent dictionary of scientific terms will guide you if you are unsure of the correct spellings or symbols of the units you are using. There is no point in using them in your writing, however, if you or your audience don't know what they mean. Symbols and abbreviations are indispensable to an engineer, but use them sparingly when writing for an audience other than your peers. You may sometimes need to define the ones you use, either in your text parenthetically (a brief explanation in parentheses following the term or symbol, like this) or with annotations:


It would be hard to do much engineering without equations. They communicate ideas far more efficiently than words at times-consider the ideas represented by E = mc2 for example. However, formulas and equations slow down your reader, so use them only when necessary and when certain your audience can follow them.

Many word-processing programs now make it easy to write equations in text, but if you have to write them in longhand do so with care to ensure both accuracy and legibility. An illegible or ambiguous equation is hardly going to communicate data effectively, and an error in an equation could be disastrous. In other words, make sure your equations are noise-free.

You should normally center equations on your page and number them sequentially in parentheses to the right for reference. Leave a space between your text and any equation, and between lines of equations. Also, space on both sides of operators such as =, +, or -. If you have more than one equation in your document, try to keep the equal signs and reference numbers parallel throughout:

Eventually you may have to incorporate multiline equations into your technical papers and reports, where they will read (and should be punctuated) just like sentences.


If you look at the early handwritten drafts of some of the greatest writers' works you'll see alterations, additions, deletions, and other squiggles that indicate how much revision went into the draft before it became a finished work. We could all produce better written documents if we always

For an engineer, time is frequently going to be a problem. You can't always find time for a leisurely edit of your work. However, you would still be ill-advised to send a first draft of anything of importance to your readers. A quick e-mail note to a friend about lunch isn't worth much concern, but anything more than this, especially if it's going beyond your immediate colleagues, needs at least to be looked over briefly with an editorial eye. How much time you invest in editing should be in direct proportion to the importance of the document. Use all the assistance your word processor will give you, including any spelling, grammar, or readability programs you may have, but don't follow their suggestions blindly. You have to be the final arbiter on the clarity and effectiveness of your work-your name will be on the document, not your word processor's manufacturer.

Editing At Different Levels

Rather than read over their finished document once or twice in hopes of randomly finding anything in need of improvement, many writers like to take a more methodical approach to editing. You might want to try this. First, check your document for TECHNICAL ACCURACY. Then decide what "writing levels" to approach your editing on, and go through your document at least once on each level. Level 1 might be the highest level of the document, where you check the overall format, organization, and appearance. Is the work arranged the way it should be? Are specifications (if any) followed? Is it the right length? Have you used the best font size, margins, and spacing? Are headings, subheadings, lists, and graphics used effectively?

Level 2 will involve looking at such things as paragraph and sentence length and structure, possible verbiage, and precise word choice. Is the tone of your document appropriate? Have you used the active voice where possible? How about transitions, parallelism, and emphasis where called for?

The final level, Level 3, is the nitty-gritty one of mechanics, spelling, punctuation-all the basics we were supposed to master in elementary and high school. As mentioned above, a good word processing program will provide you with suggestions on spelling and grammar; however, you must make the final choices on many of these options.

Collaborative Editing

There is nothing wrong with having a colleague, friend, or spouse look over your writing before you submit it to its intended audience. Two heads are usually better than one for discovering flaws in a piece of writing, and you are no longer in a freshman English class where such help might be considered plagiarism. In industry, experts often cooperate in writing technical reports, proposals, and other documents. Most lengthy documents are produced by team effort, where different team members use their particular strengths to ensure that the document is the best it possibly can be.

Collaborative editing, then, can involve something as simple as asking a friend for his or her opinion of the organization, clarity, and mechanics of your work, and using those comments to improve your writing where necessary. The more skilled and frank your friend is, the better. With a long document, however, collaborative editing can be done by having different team members check the document at different levels, which is usually better than having everyone searching for whatever they can find at all three levels at once.


The Chicago Manual of Style, 14th ed. Chicago: The University of Chicago Press, 1993.

Masse, Roger E. "Theory and Practice of Editing Processes in Technical Communication," IEEE Transactions on Professional Communication, vol. PC-28, no. 1, pp. 34-42, March 1985.

Nadziejka, David E. "The Levels of Editing Are Upside Down," Proceedings of the International Professional Communication Conference, pp. 89-93, Sept 28-Oct 1, 1994.

Rubens, Philip, ed. Science and Technical Writing: A Manual of Style. New York: Henry Holt and Company, Inc., 1992.

Weiss, Edmond H. The Writing System for Engineers and Scientists. Englewood Cliffs, NJ: Prentice-Hall, Inc., 1982.