Tables and graphs are the most common visual aids. Used extensively in all types of technical.writing, they are easily constructed from many available software programs. This section explains how to construct them and when to use them.

Basic Definitions

The information in tables and graphs is either an independent or a dependent variable. An independent variable is the group you are discovering information about. The dependent variable is the category you use to find out about the independent variable. The dependent variable changes when the independent variable changes. In a table: of weather conditions, the independent variable is the months. The dependent variables are average temperature, average precipitation, and whatever else you might wish to compare. The following sections tell you where to place these variables in tables and graphs.


Tables present information – usually numbers, but sometimes word sin columns and rows. A table shows classifications and relationships of numerical or verbal data. Here are some general principles for presenting tables.

  • In general, use tables with more professional, expert audiences. Remember that tables are harder for less knowledgeable readers to understand.
  • Refer to the table in the text.
  • Point out the essential relationships you want readers to understand. Use a table when you must present all the numerical data to expert audiences so that they see the context of the relationships you point out.
  • Use ab able to compare many numbers or features (and eliminate the need for lengthy prose explanations).
  • Pu t the items you want to compare (the independent variables) down the left side of the table in the stub column. Put the categories of comparison (the dependent variables) across the top in the column headings. Remember, columns are easier to compare than rows.
  • Use plenty of white space between columns and above and below the table.
  • Give each table a number and a clear, concise title.

The following table shows the elements and organization of a table.

Production Rates and Labor Costs


Note: Labor contract will expire Jan. 1.
‘Rounded to the nearest cent.
“Based on 1 man working at S7.DO/hour.
‘Based on 1 man working at 58.3D/hour.
dl Cycle = 20 seconds for cutting + 90 seconds iot assembly
= 110 seconds.
<Based on 1 eight-hour shift.
SOllrce:.Production Department figures for first quarter.

Guidelines for Constructing Tables

The following detailed guidelines explain how to present material in a table. The guidelines progress through a table from top to bottom. Table 1 above illustrates all of these guidelines.

  • Number tables consecutively throughout a report with Arabic numerals in the order of their appearance Put the number and title above the table. Us}: the “double number” method (for example, 2.3) only in long reports that contain chapters.
  • Use the table title to identify the main point of the table. Do not  place punctuation after the title.
  • In general, use three horizontal rules and no vertical rules. If the report is more informal, use fewer or no rules.
  • Name the independent variable in the heading of the left-hand column. Name the dependent variables (the categories you are comparing) in
    the column heads.
  • Use a spanner head to name the column headings below it. Spanners reduce repetition in column heads.
  • Use a  heading to identify the contents of the horizontal row of data to the right.

Cite the source of the data – unless it is obviously data collected for the paper. Either say “Source: Production Department figures for first quarter” or, if the table has been printed elsewhere, give a citation. Place explanatory comments below the bottom rule. Use the word Note followed by the comment. Use specific notes to clarify portions of a table. Indicate them by raised lower-case letters within the table and at the beginning of each  note.


A graph can present in simplified form the same statistical data as a table. Many software programs allow you to enter data as a table and then convert it into many different kinds of graphs. Bar graphs, pie charts, and line graphs present information more dramatically than tables, though often not as specifically. Since graphs are more dramatic but less precise, you should determine whether a table or a graph is more appropriate for your readers’ needs.

Guidelines for Selecting a Graph

If you decide to present your information graphically, you must determine whether a bar, pie, or line graph is best.

  • Use a line graph to depict trends or relationships. In a trend, the same  data change over time. The population figures for one city at different points in time is an example of a trend. A relationship shows the interaction of two variables, for example, percentage of pollutant to size of latter.
  • Use a be graph to compare discrete items. For example, the population of three-different cities at one point-in time can be shown using a bar graph.
  • Use a pie chart to represent discrete values as parts of a whole. If you
    want to compare profits to total income, use a pie chart.
  • Research shows that bar graphs are the easiest for less knowledgeable readers to grasp.

Guidelines for Presenting Graphs

The following guidelines explain how to present the title and number of graphs clearly.

  • Refer to all graphs as figure s, and number them sequentially through out the report, using Arabic numbers
  • Place the word Figure (or its common abbreviation Fig.) and the number
    at the left-hand margin.
  • Treat the word figure consistently. Either use all capital letters  or capitalize just the first letter (Figure). Place a period after the number, if the title follows on the same line. If you place the title underneath the number, do not use a period.
  • Place the title after the number or below it. Both methods are used. Do not underline the title; do not use a period after it; use initial capitals only, followed by lower-case letters.
  • In informal reports, writers place the title either below (as in this book) or above the figure, whichever is dearer in the page makeup. (Many software programs automatically place the titles above the figure.) .
  • If needed, start a second line directly under the first letter of the title. Indicate the source of the data by placing the word Source under the  figure, followed by the citation.
  • Refer to the graph in the text. Point out the relationship you want readers to understand.

Bar Graphs

A bar graph uses rectangles to indicate the relative size of several variables. Bar graphs contrast variables or show magnitude effectively. (See Figure 7.1.) A bar graph compares the items by means of the height or length of the appropriate .bars. Bar graphs can be either horizontal or vertical, depending on whether the bars go up the page or across it.


(thousands of tons)


Bar Graph
SOlaCt’: 1986 Program Strategies. Reprinted by permission of the City of Dayton, Ohio.

Vertical bar graphs (frequently called column graphs) are better for showing  discrete values over time, such as profits at certain intervals. Either typecan be used in most other instances. The following guidelines explain how to construct bar graphs more . effectively: These guidelines are for vertical bar graphs. Rearrange items accordingly for horizontal bar graphs.

  •  Place the names of the items you are comparing – the independent variable – under the bars (for a vertical bar graph).
  • Place the units of comparison – the dependent variables (usually numbers) – at the left.
  • Make the spaces between the bars one-half the width of the bars. (Many computer programs do not follow this guideline.) Use a legend – a small sample of the markings and brief phrase to explain the meanings of the bars’ markings.

Notice how the bars in Figure 7.2 are subdivided to show an additional comparison of percentages. Figure 7.3 shows a multiple bar simple where



These figures include building rental fees only.
Concession fees are not included.

Divided Bar Graph
Source: 1986 Program Strategies. Reprinted by permission of th c City of Dayton, Ohio.



Figures are adjusted to reflect changes in the Metropolitan Area.

Multiple Bar Graph
Source: 1986 Program Strategies. Reprinted by permission of the City of Dayton, Ohio. more than one bar is used to compare quantities; this device is useful when the comparison must extend over several years. Notice the legends in Figures
7.2 and 7.3.

Line Graphs

A line graph shows the relationship of two variables by a line connecting points inside an x (horizontal) and a y (vertical) axis. These graphs usually show trends over time, such as profits or losses from year to year. The line connects the points, and its ups and downs illustrate the changes’- often dramatically. Choose a line graph if you want to emphasize continuity; choose a bar graph if you want to emphasize the relative size of each item.  shows the public’s perception of park safety over a series of years. The ratings of increases and decreases in park safety are ·easy to grasp. Notice that percentages appear at each year to indicate precise numbers. The following few general guidelines show how to make line graphs more effective . Name the independent variable – the one that changes automatically such as years – on the horizontal axis.



Line Graph
Source: 1986 Program Strategies. Reprinted by permission of the City of Dayton,

(for major Ohio metropolitan areas)

Multiple Line Graph
Source: 1986 Program Strategies. Reprinted by permission of the City of Dayton,

  • Name the dependent variable – the one that changes because the independent variable changes, like profits – on the vertical axis. If m ore than one line appears in the graph, use a legend to explain each.
  • Don’t use too many lines. If you use several lines, make them ‘visually distinct (for example, use a dotted line and a continuous line.

In Figure 7.5, a multiple line graph, several lines compare the same information (unemployment rates in several cities) over the same time period. A legend explains what each line stands for.

Pie Charts

A pie chart uses segments of a circle to indicate each segment’s percentage of a total. (See Figure 7.6.) The whole circle represents







Although visual aids can increase the impact of a report, they can also overwhelm-and confuse a reader. Tables, and even graphs, may contain so much information that readers can interpret them in various ways – and perhaps not in the way you intended. As a report writer, you must learn how to guide your reader through your visual aids. This section gives the guidelines for writing about visual aids, how to refer clearly to visual aids, and how to tell readers what to notice.

Refer the Visual Aids
Refer to the visual aid by n umber. If it is several pages .away, include thepage number in your reference. You can make the references textual or parenthetical.

Textual Reference A textual reference is simply a statement in the text itself, often a subordinate clause, that calls attention to the visual aid. Parenthetical Reference The parenthetical reference names the visual in parentheses in the sentence in one of two ways: complete or abbrcvi As seen in Table 1 (p. 10)  If you look at The data In Table 1 show .

 The complete reference is used more in reports; the abbreviated in sets of instructions. In reports, use “see” and spell out “Table.” Although “Figure” or “Fig.” are both used, “Figure” is more acceptable in formal writing. The profits for the second quarter A cost analysis reveals that we must reconsider our plans for purchasing new printers (see Table 1). bIn instructions, you do not need to use “see”; you can refer to figures as “Fig.” Insert the disk into slot A (Fig. 1). Set the CPM readout (Fig. 2) before you go on to the next step.Do not capitalize “see” unless the parenthetical reference stands alone as a separate sentence. In that case, also place the period inside the parentheses. All of this data was described above. (See Tables 1 and 2.) All of this data was described above (see Tables 1 and 2).

Tell the Reader What to Notice When you discuss a visual aid, point out what the reader should look for and explain its significance. To point out an item, you simply call attention to it or name it. To explain its significance, you either give its source or discuss its implications. Examples are given in the following discussion.

Explaining a Table Table 1 in the following example is from a complex government report on the costs of having a window constructed in a wall. But the numbers can be confusing, and the important relationships are not apparent. Should we compare the cost of a 12-foot-square window ($52.20) with the cost of 12 square feet of wall ($33.72), or to some other  number or combination of numbers? Should we compare the $52.20 in the upper left-hand corner with the $216.63 in the lower right-hand corner? But why? And what would such a comparison mean? The of the table  were aware of this problem, so in {he text they pointed out which number the readers should notice and it The authors draw attention to the $18 figure in Column 1 and show its relationship first to the other figures in that column and then to the range in the “double-glazed” row. They also attempt to explain, by  the statement in parentheses, an important fact that the reader must  interpreting their data.

Acquisition Costs
Having calculated the energy costs associated with different window configurations, let us now tum to the costs of acquisition,  maintenance, and repair. The purchase and installation of  windows in a new home are generally more expensive than the costs of an equivalent area of non windowed wall. To estimate the additional acquisition costs, window costs are compared with wall costs in Table 1. This table shows that the costs of the purchase and installation of good-quality wood windows are estimated to add between $18 and $76 to initial building costs for single-glazed windows, and $48 to $216 for double-glazed windows, depending on their size. (Because windows displace portions of the wall, they raise initial building  costs by substantially less than their full purchase and installation costs.) If management devices are used, additional acquisition  costs are incurred. Costs of Venetian blinds and wooden shutters based upon averages of currently quoted prices in the Washing ton, D.C., area are given in Table 2 [not shown).

Acquisition Costs 01 a Window’ ln Excess 01 the Cost 01 a No windowed Wall


Explaining a Graph These same authors also included a complex graph (Figure 1 below) in their report. Exactly which relationship their readers should focus on is not immediately clear. Should they notice just electricity or just gJS points? Or north or south points? Should they compare N (eke) with S (gas)? And why? What do the comparisons show?


Estimated Yearly Energy Costs with North (N) or South (S) Facing Window with Gas or Electric (Elec)
Source: Belinda Collins. et al., A New Look at Windows. Reprinted by permission
of the U.S. Department of Commerce. National Bureau of Standards. Center for
Building Technology.

‘The authors solved the problem in their discussion. In the discussion the authors first make a general point, then give a specific example. So in the paragraph discussing Part B of the graph, the second sentence points out that “costs are lowered,” and the third sentence points out an exact detail to notice – that costs are 530 lower. The $30 is the difference between N (elec) at $120 in Part A and N (elec) at $90 in Part B. Figure 1 shows the estimated yearly energy costs for the room as a function of the window. Note that on the vertical axis, or zero window area, energy costs are given for a windowless room. To determine the opeating costs attributable to just the window, the yearly operating costs for a room with a given window area must be subtracted from those for a windowless room with zero window area. Part A of Figure 1 demonstrates that, when only thermai loads are considered, estimated yearly energy costs increase for both northern and southern exposures as the size of the single-glazed window increases. A window with a northern exposure has greater energy costs, however, than one with a southern exposure, particularly when the more expensive electric heating is used. The added  energy costs for the room are as much as $20 to S25 more per year for large window areas on the north wall with electric heat than for large windows on the south with gas heat.Part B plots similar yearly energy costs for a’ room with a  double-glazed window. When double glazing is used, energy costs are lowered for both orientations, For example: double glazing lowers energy costs by about $30 per year for the largest north-facing window in the electrically heated room. The reduction is somewhat lower for the south-facing window.


As a result of the impact of computers, the visual aspect of technical writing is something that all writers must master. This chapter explains how to format Pd~es to enhance the message and how to construct strong visual aids. Page formatting allows you to design a page that is easy to read, that calls attention to key items, and that helps the reader follow the contents. Writers must learn to construct head systems with various levels and to use these heads consistently throughout the document. The capabilities of the personal computer now allow the writer to design pages that incorporate element”  boldface type, various typefaces, type sizes, rules
than were eyer used in documents formatted on the must also le.un w hen to use and how to construct a wide .

aids, including tables, bar graphs, line graphs, and pie charts. Visual-aid software now enables writers to choose many attractive ways to present data.


  • Decide on how many levels of heads you will need.
  • Select a style for each level. Choose styles that reflect the descending
    levels of heads.
  • Select outside margins.
  • Select a location and format for your page numbers.
  • Choose a method for distinguishing visuals from the texf. Will you enclose
    them in a box or use a rule above and below?
  • Determine the number of columns. Decide the amount of space between
  • Do you need to place the header or footer area?


  • Name the’audience for this visual aid.
  • What do your readers known about the topic all which this visual aid is
  • What is your goal for them after they review your visual aid?
  • Do you want them to have precise data?
  • Do you want them to get an overview of the topic?
  • Do you want them to see a picture that conveys some kind of emotional drama?
  • Choose a  for this aid:
  • Determine where you’ will place its number and title (above?

The following pages present the same report section for four different formats. They illustrate the variety you can use in formatting reports. Each is the result of a different style sheet.


At Hobbes, we are concerned about two printing features: printing speed and automatic speed adjustment. Printing speed is the rate, measured in feet per minute, at which the system can print information clearly on a carton. This is important to Hobbes because we have an average line speed of 150 feet per minute (fpm). Therefore, a system that can print at least 150 fpm is required. Automatic speed adjustment is a feature that allows the system to automatically sense the line
speed and print accordingly. This is a desirable feature because when a speed variation occurs on the line, an operator does not have to be present to make the manual adjustment. Management has given this consecrations highest priority.
Capabilities  System. As Table 2 shows, the system has a maximum printing speed of 100 . This is less than the acceptable rate of speed required by the Hobbes system does not have an automatic speed adjustment feature see  Thus, an operator would have to be present at all times to monitor line speeds and make necessary adjustments. Spiff System. As Table 2 shows, the Spiff system has a maximum printing speed of 200 fpm. This exceeds Hobbes’s current line speed of 150 pm. The system has an automatic speed adjustment feature (see Table 2). This feature is economical because it saves time and, reduces the frequency of illegible printing on cartons. Conclusion. The Spiff system meets the requirements for printing speed and automatic adjustment. The Zorg system meets neither of

Printing Features of Ink Jet Printing Systems


Traditional Typed Page: Underlined Heads


At Hobbes, we are concerned about two printing features: printing speed and automatic speed adjustment. Printing speed is the rate, measured in feet per minute, at which the system can print information clearly on a carton. This is
important to Hobbes because we have an average line speed of 150 feet perminute  fpm). Therefore, a system that can print at least 150 tpm is required. Automatic speed adjustment is a feature that allows the system to automatically sense the line speed and print accordingly. This is a desirable feature because  when a speed variation occurs on the line, an operator does not have to be present to make the manual adjustment. Management has given this criterion second highest priority.

Zorg System

As Table 2 shows, the Zorg system has a maximum printing speed of 100 fpm. This is less than the acceptable rate of speed required by the Hobbes Corporation. This system does not have an automatic speed adjustment feature (see Table 2). Thus, an operator would have to be present at all times to monitor line speeds and make necessary.

Spiff System

As Table 2 shows, the Spiff system has a maximum printing speed of 200 fpm. This exceeds Hobbes’s current line speed of 150 fpm. The system has an autocrat speed adjustment feature (see Table 2). This feature is economical because it saves time and reduces the frequency of illegible printing on cartons.

The Spiff  meets the requirements for printing’ speed and automatic adjustment.  system meets neither of these requirements.


Printing Features of Ink Jet Printing ~ystems


At Hobbes, ‘Ie are concerned about two printing features: printing speed and automatic speed adjustment. Printing speed is the rate, measured in feet per minute, at which  the system can print information clearly on a carton. This is important  Hobbes because we have an average line speed  150 feet per minute . Therefore, a system that can  at least 150  is required. Automatic speed  is a feature that allows the system to automatics: !sense the line speed and print accordingly.

Printing Features of Ink Jet Printing System


does not have the ability to print a bar code. However, an option. can be added to the system, at an additional cost of $700, to print readable bar codes (see Table 1).

Spiff System. As shown in Table 1, the basic Spiff system has the ability to print a readable bar code.  This ability is part of the system and it requires no additional investment.

Conclusion. Both systems have the ability to print a readable bar code; however, the Zorg system requires an additional expenditure for this


Printing Capability of an Ink
Jet Printing. System


Printing Features At Hobbes, we are concerned about two printing features: printing speed and automatic speed adjustment. Printing speed is the rate, measured in feet per minute, at which the system can print information clearly on a carton. This is important to Hobbes because we have an average line speed of 150 feet per minute (fprn). Automatic speed adjustment is a feature that allows the system to automatically sense the line speed and print accordingly. Management has  given this criterionsecond highest priority. Zorg System. As Table 2 shows,
the Zorg system has a maximum printing speed of 100 fpm. This is less than the acceptable rate of speed required by the Hobbes Corporation. This system does not have an automatic speed adjustment feature (see Table 2).

Spiff System. As Table 2 shows, the Spiff system has a maximum printing speed of  00 fpm. This exceeds Hobbes’s ,current line speed of 150 fpm. The system has an automatic speed adjustment feature

Printing Features of Ink Jet
Printing Systems



  1. Photocopy a table from the Statistical Abstract of the United States, available
    in your library’s reference room. Convert the data in the table into a graph that illustrates a relationship you can see in the table. Write a paragraph explaining the relationship shown in the table and another explaining the same relationship in the graph.
  2. Find a line graph and convert it to a bar graph, or vice versa. Write a brief paragraph explaining each one. Emphasize the trend in the line graph; emphasize the discrete data in the bar graph. Photocopy a table or graph, and its accompanying explanation, from a report or a journal. Bring it to class, and in small groups discuss the strengths and weaknesses of the explanations.
  3. If you have access to a computer graphics program, make several different graphs of the same data. In a brief paragraph, explain the type of reader and the situation for which each graph would be appropriate. Divide into groups of three or four, by major if possible. Select a process you are familiar with from your major or from your campus life.
  4. Possibilities include constructing a balance sheet, leveling a tripod, focusing a microscope, constructing an isometric projection, threading a film
    projector, finding a periodical in the library, or making a business plan. As a group construct a flow chart of the process. For the next class meeting each person should write a paragraph explaining the chart. Compare paragraphs within your group; then discuss the results with the class. Select one of the visual aids from  Write a brief (one to two paragraphs) news release about it for a local newspaper. Assume that you are the public relations manager in a large city government.
  5. Convert the following paragraph into a table.  Then rewrite the paragraph for your manager so that you give only the essential information. This store sells two brands of jewelry, High Fashion and Golden Moment. For each line we carry earrings, necklaces, bracelets, rings, and pins. The High Fashion jewelry lists the following prices for these pieces, respectively:  $4.00,$7.00, $5.00, $35.00, and $8.00. The Golden Moment line lists the following prices, respectively: $8.00, $10.00, $7.00, 522.00 and $12.00. Except for the rings, High Fashion is cheaper by these amounts, respectively: $4.00, $3.00, $2.00, and $4.00. Golden Moment’s rings are $13.00 cheaper.
  6. Divide the class into three sections. Have individuals in each section convert the following numbers into visual aids. Have Section 1 make line graphs, section 2 make bar graphs, and section 3 make pie charts. Have one person from each section put their  (In the board. Discuss them for effectiveness. Here are the figures: Respondents to a survey were asked if  pay more for a tamper 8.2% said they would more: 25.8% were unwilling to pay more; 51.6% would pay $.05 more, al’.:] 14.4% would pay $.10 more.
  7. Make a pie chart about some aspect of your class. An easy topi c is the percentage of students from cities of various sizes – over 100,000, between 50,000 and 100,000, and so on. You will have to collect all the data and compute the percentages in class. Outside of class, make a bar graph of the same data. Write a story of several paragraphs for the school newspaper, explaining the diversity or homogeneity of your class. Refer to specific parts of your visual aid.
  8. Read over the next four paragraphs from a report. Then construct a visual aid that will support the writer’s conclusion.
  9. Apple works. The Apple works reference manual is very well written, with a detailed table of contents and numerous helpful examples. It has “Apple works lips,” altering helpful hints for efficient approaches to common tasks, and “warning” messages for problem areas. For experienced users, the manual has a’list of  command shortcuts to speed up the processes.Apple includes a tutorial, which consists of a series of carefully designed, interactive learning experiences. The tutorial leads the user through the basic commands, keystrokes, and features, providing explanations and sample tasks. Packaged on two disks and covering key topics, it is designed to  allow the user to proceed at his or her own pace. Topics can be started, ,repeated, or skipped as the user sees fit.

Big worker. The Big Worker manual serves its intended purpose fairly well, with it1ew exceptions. It contains no mention Of the sample data diskette, nor does it mention that the examples shown in the manual are contalned on the sampJedata diskette. It has many boldface “remember” messages that explain what will happen if the user performs certain actions. This feature is an attempt to prevent user mistakes. Overall, its reference section contains inadequate detail and no detailed system overview. No disk tutorial is available.

 Conclusion. The documentation supplied with Apple works P-8f’ioJin all respects.

Works CITED Collins, Belinda, etal. A New LDUka/ Willdows. NBS}R 77-1388. Washington, DC: National Bureau of Standards, 197H.



Deciding which type of visual aid to use is sometimes difficult. The best way to choose is to decide what your readers need. If your readers need  more scientific or “more objective” data, use tables and line graphs. Tables can classify large amounts of data so that relationships can be easily pointed. out. Pie and bar graphs have more visual impact or drama. If you look back at the bar graph shown in Chapter 1  you will see that it presents information dramatically. The towering columns clearly reinforce the notions of “critically important” and “important” as opposed to the short column of “no importance.” The difficulties – and ch  of deciding what visual aid to use can be seen in the following figures. All four figures, constructed using Microsoft are attempts to convey the material presented in the table in Figure 7.14. The table compares the costs of manufacturing WORM disks (a type of computer floppy disk) from 1980 to 1987 in four areas: testing, thin films, assembly, and coating. The four types of figures consist of a divided bar graph, one bar for each year ( two bar graphs, one for each year  a bar graph showing bars for each component(Figure  and two pie charts, one for each year  Notice the effects. The two bar graphs  emphasize changes in the relationship between items in each year. It is easy to see the relationships between.

Table 1.
Components of Cost of Disks


A Table Compares the Data


A Divided Bar Graph Compares the Data
testing and thin films for each year, but the two vertical axes (“Dollars”) are based on different scales, so comparison is difficult. The two pie charts (Figure 7.18) take time to figure out because they are separated from each other. Notice that they do show that the total cost has change~’and that the relative percentages of thin films and testing have changed .
The divided bar graph  shows the. relationships between the components and the total cost. This visual shows essentially the same information as the two pie charts. Because of the closeness of the two columns, however, the comparative relationships are easier to grasp. The bar graph with two columns for each component  contrasts dollars, not percentages, clearly illustrating all the reasons why 1987 is cheaper overall than 1980. If readers need to understand dollar breakdowns,  would serve their needs better. If readers need percentage breakdowns, the divided
bar graphs or the pie charts   would help them more. However, jf readers need precise figures and if they can’ work easily with relationships, the table would be a good choice .


Two Bar Graphs Compare the Dala


Multiple Bar Graph Compares the Data


Two Pie Charts Compare the Data

Three Principles for Manipulating Graphs
Ian  in his book Using Charts and Graphs, illustrates three ways that you can affect the perception’ of graphic data. Your goal. is to present the graph so that it reports the data honestly

  1. Changing the width of the units on the y-axis alters the viewer’s’ emotional perception of the data. The following graphs plot exactly
    the same data (Figure 7.19).

    Three Graphs Plot the Same Data
    Solution: Reprinted by permission of R. R. Bowker

  2. The nearer a highlighted feature appears, the more impact it has
    on one’s consciousness. The following pies report the same data.
    Notice that the wedge on the left appears largest, but the wedge on
    the righfis forced into the viewer’s consciousness. The middle wedge
    appearsunimportant because it is far away (Figure 7.20).
    1Three Pie Charts Plot the Same Data
    SOli Tee: Reprinted by permission of R. R. Bowker
  3. A darker element seems more important to the viewer (Figure 7.21).
    Three Bar Graphs Plot the Same Data
    Source: Reprinted by permission of R. R. Bowker.



A chart is the catchall name for many kinds of visual aids. Charts represent the organization of something, either something dynamic like a process, or something static like a corporation. They include such varied types as troubleshooting tables, schematics of electrical systems, diagrams of the sequences oE an operation, organization charts, flow charts, and decision charts. Use the same techniques to title and number these as you use for graphs. (Some software companies, like Microsoft, use chart to mean graph. You will find these terms are used inconsistently.)

Troubleshooting Tables
Troubleshooting tables in manuals identify a perceived problem and give its probable cause and cure. The problem appears at the left and the appropriate act on to the right. Complicated tables, like  also suggest causes. Service manuals for huge manufacturing machines and user manuals for appliances, VCRs, and automobiles use these tables.

Organization Charts
Organization charts depict the flow of authority in an institution.  They are composed of boxes (with names and positions in them), and lines connecting the boxes. Place the most powerful position at the top and less powerful positions below.

Troubleshooting Table


Troubleshooting Table
Source: Reprinted by permission of MRMlElgin.

Flow charts

Flow charts symbolically depict a time sequence or a decision sequence. A flow chart has arrows that indicate the direction of the action, whatever it is, and symbols that represent steps or particular points in the action.  In many instances, especially in computer programming, the symbols have special shapes for certain activities. For instance a rectangle means an action to perform and an oval means the first or last action. Flow charts are especially helpful when you must to help a reader  a process.




Flow Chart


Decision Chart

Decision Charts
A decision chart (or tree) is a flow chart that uses graphics to explain whether or not to perform a certain action in a certain situation. At each point the reader must decide yes or no, then follow the appropriate path until the final goal is reached.



Illustrations, usually photographs or drawings, are used extensively in sets of instructions and manuals. To point out the important parts of an illustration, writers use callous, letters or words connected by lines to the relevant
part of the illustration. The following general guidelines explain how to make illustrations more effective Use illustrations to avoid lengthy discussions. A picture of a complex

  • pint will generally be more helpful than a lengthy description.
  • Use high-quality illustrations: make sure they cue clear, and large enough to be effective, and set oif by plenty of white space.
  • Keep the illustrations as simple as possible. Show only items essential for your discussion.

Photographs are difficult to use in technical reports because,’ in order to be reprinted, they must be converted to halftones. This process changes the photograph into a series of dots, which until recently only the printing press could reproduce. Computer technology has partially solved this problem with scanners, devices which convert photographs into halftones electronically. These expensive devices produce acceptable but low-quality halftones. A writer inserts a photograph into a scanner, which electronically  converts the photograph into dots. Using a scanner and an instant camera, many amateurs can produce acceptable halftone photographs in minutes. Drawings are easier to reproduce. A scanner will produce good reproductions of line drawings, since they do not have to be converted to halftones. Anyone with a scanner can easily convert. a line drawing on a sheet of paper into electronic dots.


A good photograph has these advantages: it duplicates the item discussed (so audiences can be sure that they are looking at what is intended), and it shows the relationship of various parts. The disadvantages are that it reduces a three-dimensional reality to two dimensions and that it shows . everything, thus emphasizing nothing. Figure 7.7 shows a skillfully “cropped” photograph. The original contained much more visual information, but the designer blocked out a great deal of it, simplifying it so it makes only one point.


Drawings, whether made by computer or by hand, can clearly represent
an item and its relationship to other items. Since details in drawings are


Cropped Photograph
Source: A manual by Jill Adkins. Reprinted by permission of MRM Elgin.

chosen selectively by the artist, the reader can focus on just the intended  object. The exploded view and the detail drawing are two commonly used types of drawings.

Exploded View As the term implies, an exploded view shows the parts disconnected but arranged in the order in which they fit together, as in Figure 7.8. Exploded drawings can show the internal parts of a small and intricate object or explain how it is assembled. Manuals and sets of instructions often use ~xploded drawings with ‘named or numbered parts.

Detail Drawings Detail drawings are renditions of particular parts or assemblies. They are used in manuals and sets of instructions, usually in one of two ways. Drawings can function as an uncluttered, well-focused photograph, ‘Showing just the items that the writer wishes, They can also show cross-sections, that is, they can cut the entire assembled object in half, both exterior and interior. In technical terms, the object is cut at right” angles to its axis. A cross-sectional view shows the size and relationship of all the parts. Two views of the same object, front and side views, for example, are often placed beside each other to give the reader an additional respective of the object. (See Figure 7.9.)


Exploded View
Source:  Controls: Independent Study Workbook by John R. Mancosky. Used by permission of Micro switch and John R. Mancosky.




Visual aids have always been an essential part of technical writing. With the advent of graphics programs for personal computers, writers have available a number of choices for using visual aids. Computers easily convert data to many kinds of visuals. The bar graphs, line graphs, and pie charts (Figures 7.1 to 7.6) shown in this chapter are all computer-generated. This chapter explains a number of different types of visual aids, shows how to discuss them in the document, and tells when to use them.

Three basic types of visual aids are tables and graphs, illustrations, and charts.

Guidelines for Effective Visual Aids

These six guidelines provide a framework for incorporating visual aids into a document. Later sections of the chapter explain which types of visual aids to use and when to use them.

  1. Construct high-quality visual aids, using clear lines, words, numbers, and organization. Research shows that the quality of the visual aid is the most important factor in its effectiveness.Identify all visual aids as either tables or figures. Anything that is not a table is a figure – no matter what form it takes. In formal situations, place numbers and titles directly above tables and directly below figures. For informal situations, you may place the titles (and numbers if you use them) above or below, whichever seems clearer.
  2. Make sure a visual conveys only one point. If you include too much data, readers cannot grasp the meaning readily. Do not clutter a visual aid with too many words or lines, causing it to lose its visual quality and impact. Integrate visual aids into the report at logical and convenient places. As a general rule, place illustrations in the middle of or after your discussion them.
  3. Refer to each visual aid in the text, (usually by number, e.g. “see Figure I”), even if the illustration is right beside or below your discussion of it, and explain or interpret each one.



To format is to make choices that affect a page’s appearance. The phenomenal growth of word processing and the ready availability of desktop publishing programs and laser printers mean that writers must understand formatting. This section explains three basic formatting areas:

  1. How to design a page
  2. How to emphasize material
  3. How to use heads to indicate contents

How to Design a Page

To design a page means to arrange it so that it effectively presents the contents to the reader. Good design makes a document easier to read. Software programs such as ‘Microsoft Word, Word Perfect, Page  and Ready, Set, Go! now give writers the ability to manipulate the elements of design. This section explains those elements, then gives some guidelines for using them effectively.

The Elements of Design

The major elements of design are rules margins columns typefaces justification  page numbers.

A rule is-a line. Its width is measured in points, a typographical term. One point is 1172 of an inch. Rules are designated by their width: “I point,” “2 point,” and so forth. The margin is the white space between the edge of the paper and the body of text. Columns are vertical lines of ·type; a normal typed page has one wide column. Many word-processing programs allow up to twelve narrow columns; in practice, however, reports seldom need more than three columns. Some report writers are beginning to use two columns. Every typeface (often called  in word-processing software) is named; some frequently used typefaces are Times, Helvetica, and Palatino. Typefaces are divided into two major groups: serif and sans serif. Serif faces have extenders at the ends of straight lines in letters. Sans serif do not have the extenders. Serif faces impart a classical, more formal impression whereas sans-serif faces appear more modern and informal. Serif Technical writing makes the world go around.

Sans Serif Technical writing makes the world go around.  Justification means aligning all the first or last letters of the lines of a column. Documents in English are almost always presented “left justified”  all the first letters of each line start at the left-hand margin. Right justified means to align at the right-hand margin all the letters that end lines. Page numbers appear either in the upper right corner or at the bottom middle of the page. Each piece of paper counts in the sequence of pages even if no page number appears on it.

Guidelines for Using Design Elements

Guidelines for using these design elements follow:

  • Generally use f-inch margins on the top, bottom, left, and right. Use inch margins on the left if you are going to bind the paper.
  • Avoid right-justified margins. Many word-processing programs achieve right justification by inserting too many spaces between words or else by excessive hyphenation, Both methods call attention to themselves, thus distracting from the message. Do not use rules thicker than 2 points. Generally choose a hairline (or 112 point) rule. The thicker the rule, the more it dr~ws the reader’s eye. As a rule of thumb, thick rules appear above words, thin rules
    appear low.
  • Generally use a single column for reports. As shown on p. 155, for design’s sake you might want to use a 2- or inch left margin.
  • Two columns are especially useful if you plan to use a laser printer to produce a number of graphics. You can control the visual impact of the page better.
  • Use no more than two typefaces per document. In general, use the same typeface for text and heads, but you could use one typeface for text and another for heads (choose a serif face for text and a sans serif for heads). Use italics sparingly – italicized print is hard to read.
  • Place page numbers in the same position on each page. Many word  processing programs automatically number each page. (The number “1” can appear on page one.)

To see the design elements arranged for different visual effects, turn to pages 122-123. Four models illustrate different ways of designing the same page.  Developing a Style Sheet As you generate any document, you should develop a style sheet, which is a list of the ways you will treat each  design item.For instance, for a three-page memo, the style sheet would be quite short:

1-inch margin on all four sides no right justification single-space paragraphs double-space between paragraphs heads flush left and under cored triple-space above and double-space below heads page numbers at bottom middle For a more complicated document, you need to devise a much more complete style sheet. In addition to margins, justification, and paragraph spacing, you need to consider  a multilevel head system  page numbers rules for page top and bottom rules to offset visuals captions f06,visuals
headers  footers – such as whether the   placed inthe top (header) or bottom (footer) margins.

How to Emphasize

To achieve emphasis, you highlight. Highlighting means to make an item look different from the items, around it. You can highlight by using boldface, all capitals, underlining, or vertical lists. The basic guidelines for highlighting are.

  • Highlight – but not too much .
  • Use boldface as the most effective highlight (underlining is the most effective for typed material).
  • Avoid long phrases written in all capital letters .
  • Use vertical lists to emphasize the items in a series.

The following two examples illustrate ineffective and effective use of highlighting. Ineffective highlighting Caution: Do not separate the mold holders from the mold cavity with a sharp instrument. Use nothing harder than brass or
wood. You could damage the mold. Caution: DO NOT separate the mold holders from the mold cavity with a sharp instrument. Use nothing harder than brass or wood. You could damage the mold

How to Use Heads to Indicate Contents

To indicate a document’s contents, you develop a head system. A head is a  word or phrase that indicates to the reader the contents of the following section or subsection. Here are four basic guidelines for developing a head system.

  1. Designate levels of heads, traditionally called by letters or numbers (A, B, C, D, or level, level 2, level 3). Level A is a main section, level B a ‘subsection, level C a sub-subsection, and so en. Make each level look different, with the level A head more prominent than level B, and so forth. Use bold facing or underlining. Use different print sizes. Place different levels at different positions on the page (centered or flush left). Your method of printing the document will affect your options for designating heads:
  2. Make each level’s wording parallel. Use all noun phrases or questions
    or +s words.
  3. Use content wording, not generic wording. Use phrases like “Factors in Total Cost” rather than “Cost”. Use questions.

To see these guidelines in action, turn to;pp. 153–156,showing a section of a report presented in several ways. Indicating Two Levels of Head Most documents need only one or two levels of head. Most writers use-a “side left” head as the level 1 head 1/ and a “paragraph” head as the level 2 head. For level I, place the head at the left-hand margin, leave white space above and below, use no punctuation after; and either boldface or underline it. For level 2, place the head at the start of the ‘paragraph, indented five spaces, followed by a period.  Indicating More Than Two Levels of Head The remainder of this  section illustrates two different head systems, open and numbered; and both can indicate up to four or five levels of head. Examples are given for the typewriter and laser  Carefully note  letters are capitalized, how much space is above and below, and whether punctuation follows.







The numbered system, often used in more technical or more complex material, indicates level by a number before the head. Each succeeding level uses more numbers. The first level is 1.0, 2.0, etc. The second level is 1.1, 1.2; The third level 1.1.1, 1.1.2. Notice that laser-printed documents use boldface and larger type.

5 Levels – Typewriter/Basic dot matrix 1.0



5 Levels – Laser printer/Advanced dot matrix


Formatting and Visual Aids

Formatting and Visual Aids


The personal computer has caused radical changes in the individual writer’s ability to generate documents. The most noticeable change is in the way you can affect the look of a document by formatting the page.and constructing and using visual aids. In the days of the typewriter, i writer had only a few limited methods for affecting the look of the page margins, underlining, and spacing. Complicated tables, good looking graphs, maps, photos – all were out of the question. If writers wanted them in a report, they drew them in by hand or pasted them in. Now writers have many attractive methods available to them, methods formerly used only in expensive typeset material. Boldface, different typefaces, and different type sizes are all available in even the simplest programs. Since software allows writers to incorporate even complicated visuals into their documents with ease, the technical writer must now understand basic formatting and visual concepts. This chapter explains both.