Parallelism in Technical Writing

What is parallelism?

To put each item in a list or group of words in the same grammatical form (verb+ one or more nouns).

Compare the following.

Pick up mail

Call Hazlitt

Work on tailgate project

Don’t forget to ask RJ for $$

This is parallel

Mail needs to be picked up

Call Hazlitt

Tailgate project

Don’t forget to ask RJ for $$

This is unparallel

When do we use parallelism?

1. When two items being mentioned, share a coordinate relationship. For example:

Evidence that the receptor sites on the membrane can serve both for metabolite transport and for metabolite signalling has raised many questions as to the mechanisms of membrane information-transfer.

2. When two items are being compared. For example:

A pollution-free inertial-electric system has greater energy efficiency than an internal combustion engine.

Types of Lists

1. Fully Formatted:

Where alphanumeric sequencing and vertical alignment are used as formal features to make the list stand out. For example:

a. Government invoice # 79-1018A

b. Bonded Stores invoice # 31285

c. DECAS letter 5/20/79

2. Partially Formatted:

Where either alphanumeric sequencing or vertical alignment is used but not both. For example:

Factors taken into consideration, include the following: (1) size of lot, (2) parking requirements, (3) need for elevator, (4) cost per gross square foot, and (5) expected annual return per gross square foot.

3. Completely Unformatted:

Where neither alphanumeric sequencing nor vertical alignment has been used. A negative example is:

The TFC engineers and I found the selection of Hybrid Analog Transmission using FDM ( Frequency Division Multiplexer) to be highly reliable, improved security of communications; complete ground isolation, freedom from cross-talk, sparking, short circuit loading; RFI, EMI and EMP immunity.

It is difficult to understand what are the major items constituting the list in this example and what role they are playing.

Some examples1. The principle processes are:

a. Coagulating and flocculation

b. Removing the solids

c. Nitrogen-removal

d. Disinfection

This example mixes verb forms (-ing) with noun forms (-al and –tion). When written like this:

The principle processes are:

e. Coagulation and flocculation

f. Removal of solids

g. Removal of nitrogen

h. Disinfection

the list is more sharply defined and has a more professional look.

Lack of Parallelism can Mislead the readerThis filter has two important functions: to reject impulse noise signals and passing low frequency command signals without amplitude or phase distortion.

It seems here that two things are rejected: the impulse noise signals and the passing of low frequency command signals.

This ambiguity can be cleared up by using the two verbs in parallel forms:

This filter has two important functions: to reject impulse noise signals and to pass low frequency command signals...

OR

This filter has two important functions: rejecting impulse noise signals and passing low frequency command signals..

Task 1

Read the following statements and correct any mistakes in parallelism.

1. The building is 140 feet in length, 78 feet wide, and has a height of four storeys

2. The widest employment of DDT is in the control of insects of public importance ( as a mosquito larvicide, a spray for malaria eradication and to control typhus by dust application)

3. The reason for this is that most small businesses have a lower budget for their managers than do government or industrial managers.

4. In this particular case the most important variables are the following:

• To redesign the mix for concrete slabs• An evaluation of the compressive strength with

the use of test cylinders for various designs• Determining both the theoretical and actual

material costs per cubic yard

Misleading Parallelism

Parallelism is used as an aid in understanding lists and should be avoided where lists are not being discussed as the reader might end up analysing the paragraph as a list and so, misinterpret what is written.

Richard Clarke, senior systems programmer, asked me:•to develop a magnetic tape management system•to reside permanently on the computer•to give better control•to coordinate the numerous magnetic tapes

Here it seems as if this person has been asked to ‘reside himself permanently on the computer and give better control’ rather than the system he is to make.

The need here is to separate the actual list and use parallelism for the parts of the list and to write the remaining information separately.

A better version of the same information, then, would be:

Richard Clarke, senior systems programmer, asked me to develop a magnetic tape management system:•which will reside permanently on the computer•which will give better control•which will coordinate the numerous magnetic tapes

Task 2 Correct the mistakes in each of the following passages

containing misleading parallelism.

1. My present occupation is repairing typewriters, printing machines and duplicating machines.

2. You learn many reasons why our product failed by reading, observing, talking and listening to our sales people.

3. This technology consists of three methods of scrambling, which are the coupling of light source and optical fiber in low-order mode, slicing, bending and tightening the fiber near its connectors, and installing the scrambler into the existing fiber optic in intervals of 1km along the route.

Parallelism in Paragraphs and Larger UnitsIn larger units such as paragraphs, parallelism may be used to indicate the relation between two sentences. It may also show how two or more paragraphs may be related.

Failure to use parallelism can make it difficult to read quickly and selectively. For example:

All-Savers Certificates will not benefit all investors. Investors exceeding a deposit of $ 7931 ($15,861 joint return) would have an after-tax yield far lower than alternative investments such as money market funds or Treasury bills. Alternative investments would also yield better after-tax yields and no penalty if the certificate was redeemed within the 1-year maturity period.

When you skim and scan, you tend to read to first sentence and usually expect a general-to-particular structure.

Here the first sentence is the topic sentence. The second sentence supports it by describing the class of investors who would benefit more from alternative investments than Al-Savers Certificates. The third sentence appears to provide additional details about alternative investments.

All-Savers Certificates will not benefit all investors.

Investors exceeding a deposit of $7931 would have an after-tax yield far lower than alternative investments...

Alternative investments would also yield better after-tax yields and no penalty..

Task 3: Reconstruct the following passage to represent the information in a more appropriate manner using listing.

In order to meet the job requirements it became clear that a microcomputer would be required to do this type of work. Microcomputers are very compact and portable. They are easily programmed and can be used for a wide variety of data processing. These computers are normally quite easy to operate and capable of storing large amounts of data both inside and outside of the computer itself. The most attractive part of using a microcomputer is that it is very inexpensive in comparison to other large-scale systems.