Table Design

Once you have determined that a table should be used to communicate your message and have chosen the type of table that work best , you should refine your design so that it can be quickly and accurately read and understood .Fortunately it is simple and easy to learn.

Structural Component of the table

There are two major components in a table design :

• Information components  (To express information directly).
• Supporting Components   (For arranging or highlighting).

When these components are designed well, the result is clear , accurate , and efficient communication .

Information components consist of three type of information :

• Categorical labels
• Quantitative values
• Complementary text(Label, Introduce, Explain, Reinforce, Highlight, Sequence, Recommend, Inquire)  Read more in my previous post

Apart from Complementary roles, the most common use of the text in the tables are as titles and headers.

Supporting Components

The following visual objects and attributes can function as Supporting Components :

• White space = The primary visual means that we can use to impose table structure is white space. Properly used , white space  clearly organizes data objects into group without drawing attention to itself.

• Page breaks = Page break are a logical extension of white space . They can be used to group data by starting each new group on a separate page or screen .Page break would not useful to separate  group of information that are meant to be compared .(Principle of proximity)

• Rules and grids = Both use lines to delineate or highlight data . Grid are the combination of the horizontal and vertical lines that intersect to form matrix of rectangles around data .Rules are lines that run either only horizontally and only vertically and therefore don’t intersect.(Principle of Enclosure and connection).

• Fill Color = To group areas of the table together or highlight them as important and make the area stand out .(Principle of Similarity and Enclosure)

The surface on which all data and support components reside is the background . It provide a clear surface that allows information , as well as the support component that arrange and highlight the information , to stand out for easy and efficient reading .

Table terminology

Fig.8.1

Table design best practices :

Focus area are grouped into five categories :

1. Delineate columns and rows  

• White space and page breaks
• Rules and grids
• Fill Color

2. Arranging data
• Columns and rows
• Groups and break
• Column and breaks
• Column sequence
• Data sequence
3. Formatting text
• Orientation
• Alignment
• Number and date format
• Number and date precision
• Fonts
• Emphasis and color
4.  Summarizing values
• Column and rows summaries
• Group summary value
• Headers versus footers
5. Page information
• Repeat column headers
• Repeat row headers

Delineate columns and rows 

• With the white space alone whenever space allows.
• When you can`t use space , use subtle fill color.
• When you can`t use fill color , use subtle rules.
• Avoid grid  altogether.

Arranging data 

Columns or rows    

• Arrange a set of categorical subdivisions across separate  columns if they are few in number , and the maximum number of characters in those subdivisions is not too large.
• Arrange time series subdivisions horizontally across separate columns .Arrange ranked subdivisions vertically down the rows.

Groups and break

• Use just enough vertical white space between groups to make breaks noticeable .
• Repeat column headers at the beginning of the each new group.
• Keep table structure consistent from group to group .
• When groups should be examined independently , start each on a new page .

Column sequence

• Place sets of categorical subdivisions that are arranged down the  rows of a single column to the left of the Quantitative value associated with them .
• Place sets of categorical subdivisions that have a hierarchical relationship  from left to right to reflect that hierarchy.
• Place quantitative values that were calculated from another set of quantitative values just to the right of the column from which  they are derived .
• Place columns containing data that should be compared close together .

Data sequence

• Whenever categorical subdivisions have a meaningful order, sort them in that order.

Formatting  Text

Orientation

• Avoid text orientation other than horizontal , left to right.

Alignment

• Align number to the right , keeping the decimal points aligned as well.
• Align dates however you wish , but maintain a consistent number of characters or digits for each part of the date.
• Align all other text to the left .
• Center non numeric items if they all have the same number of characters, and the number of characters in the header is significantly greater.

Number formatting

• Place a comma to the left of every three whole-number digits.
• Truncate the display of whole number by sets of three digits whenever  numeric precision can be reduced to the nearest thousand, million , billion, etc.
• When negative number are enclosed in parentheses, keep the negative numbers themselves right aligned with the positive numbers.

Date Formatting

• Express months either as a two digit number or a three - character word .
• Express days as two digits.
• Express years consistently as either two or four digits.

Number and date precision

• Do not exceed the required level of precision.

Font

• Select a font that is legible , and use the same font throughout the table.

Emphasis and color

• Boldface , italicize , or change the color of the fonts when useful to group or highlight .

Summarizing values

• Make columns containing group summaries visually distinct from the details columns .
• Consider placing summaries in the group header if the information extends down the multiple pages .

Giving page information

• Repeat column headers at the top of each page .
• Repeat current row headers at the top of each page .