The Art of the Spreadsheet. Copyright 2008 John F. Raffensperger

1. Why is spreadsheet style important?
2. Make your spreadsheet read from left to right and top to bottom.
3. Omit unneeded bytes.
4. Omit unneeded sheets.
5. Organize blocks with care.
6. Attend to blank space.
7. Omit unneeded cells.
8. Format with caution.
9. Show all the information.
10. Spreadsheet errors.
11. How to audit a spreadsheet.
12. Suggestions for operations researchers.
13. Teaching the art of the spreadsheet.
Appendix. Checklist for a spreadsheet.

6. Attend to blank space.

Consider the empty margin at right. Is it likely to cost you money or waste your time? No, of course not. Are you sure it is blank? Perhaps some important text is printed there? Maybe there is an important footnote over there that refers to something from the preface? No, of course not. Blank space in print has a purely visual effect. It does not hide anything and is not accidentally covered by nearby information. Otherwise it is not blank. Blank graphical space is benign. Blank graphical space is not even remotely like blank space in a spreadsheet.

Blank space in a spreadsheet can confuse you, waste your time, and deceive you outright. This could cost you money. A spreadsheet cell is a discrete object. It can be formatted in the same color as the background. It can be formatted as hidden. It can be blank, but perversely another cell can depend upon it. A blank cell may appear to contain data that is really in a different cell.

By visually confusing blank with information, the writer forces the reader to move the cursor to find where information is located. Even though the reader can see the data, he cannot see which cell contains it. It is almost like the cell with the data has escaped from where it should be.

How do these problems come up? How can they be avoided? By following a few rules, you can help your reader find information easily.

Keep the grid on.

Keep the spreadsheet's default grid on so your reader can see individual cells, so cells remain visually identifiable rather than hidden. Show blank space.

In the first two sheets here, it is unclear which cells contain some of the labels. In the left screen, we do not even think of asking which cells contain which data, since we cannot see any cells. In the middle screen, we can see the cells, but their relation to the information is not always clear. How are columns A and C used? Is Preference Total in column B, C, or D?

In the left and middle, the Preference Total label seems right justified in cell D4. In fact, both C4 and D4 are blank. The label is in cell B4 with leading spaces. The leading spaces were put there to move the label closer to the formula, to cross the C column. The spaces are unnecessary and should be deleted; the label should be put in cell A4 and left justified. Only in a spreadsheet can data appear to be in one place but actually be in another! In the bottom right sheet above, there is no ambiguity. Information is clearly contained in specific cells.

Tufte, Edward, Envisioning Information, 1990, Graphics Press, Cheshire, Conn., pp. 55, 62-63.

Tufte favors no grid. Ideally, information should be “transparently organized by an implicit typographical grid, defined simply by the absence of type.” In print, the “the cell is here” grid no longer gives any information. We do not want to have empty boxes pointed out to us. If you feel you need a grid, use delicate gray lines, and only for the parts of the spreadsheet that absolutely require it.

On screen, unfortunately, a spreadsheet's cells are objects that we need to be able to find. Cells are not the same as blank, even when empty. So many problems arise, and we must compromise a bit. Especially on screen, the default grid is useful to show us the location of each cell. The grid displays the cells as objects, which they are. Anything beyond this is probably chartjunk.

Ambiguity in blank area also results from merged cells. Merged cells are one of those negative features - you can do it, but you probably should not. Here, a merged cell in row 4 spans columns A through F. The heavy border is the cursor, not a format. The writer apparently merged the cells to allow convenient centering of the title, “Ansto Anamarisa.”

With the color and text removed, we see that rows 1 and 2 also had merged cells. Again, this was apparently to allow a centered title.

The writer was trying to produce a template that would look like a glorious brochure. It seems to me that this confused an accounting chore with writing a community newletter.

Merging cells is an advanced option that most spreadsheet writers and readers do not know. Upon moving the cursor into a region with merged cells, the reader is likely to experience confusion rather than a sense of artistic pleasure at the writer's cleverness. Where did the other cells go? If I want to change the spreadsheet, how do I get them back? Are there other merged cells? Merged cells tend to raise unnecessary questions in the reader's mind.

For better readability, cells should be the way they look and the way readers will probably expect. The obvious expectation is a complete two-dimensional grid of cells. A minimum of blank space helps keep the spreadsheet on fewer screens, and helps avoid an impression of hidden or misplaced information. Avoid unnecessary spacing with rows or columns. Instead, use careful alignment and justification.

Make active cells look full. Make empty cells look blank.

Graphical blank cannot be covered by nearby information. But a blank cell may appear to have data that is really in another cell.

Where is the label “Surplus = $1 Million”? Is it in one of cells I32, J32, K32, L32, or M32? In fact, it could be in yet another cell.

This is really the same problem as the Preference Total cell we saw above, just more egregious. There is no way to know where this information is located, except to move the cursor around and look for a formula in the formula bar, and hope it is not hidden. This is a lot of work for the reader. The confusion often results from long labels. Try to avoid labels that overlap neighboring cells.

Here, cell I33 contains a big formula. It's not truly blank, though it looks blank.

Avoid string arithmetic that can display blank, e.g.
=if(condition, show data, " ")
which shows a blank if the condition is false. At least show something, such as:
=if(condition, show data, ".")
Now, if the condition is true, at least the reader can see that the cell is active. But the best thing to do would be to show data that is of the same type (string or value) as the data in the true clause. If the condition is true, the statement shows some data of some type, probably numerical. If the condition is false, the statement should show data of the same type. More on this later.

Information in one cell logically should be in that cell visually. Make blank cells look blank. Make active cells show information. Do not write in invisible ink.

A cell can be blank, but another cell can depend on it. If cells depend on blanks, the spreadsheet is perverse. It is wrong because it is blank. References to blanks are like vagueness in legal writing - dangerous.

This error is most common when precedence arcs are too long and do not point the way we read. Here, if the writer had put a 0 in cell Z19, we wouldn't be worried. It would look strange, but may not be wrong. But we can see the writer probably made a mistake.

How can blank space be used effectively? Though empty cells are not equivalent to blank space in a graphic, empty cells can be used in the same way, if the writer is careful. The writer can separate blocks with blanks as one separates sentences with a period or paragraphs with an indent. But arrange the data types so there is a reasonable minimum of punctuation. Small blocks can be adjacent without blank space between.

Use a minimum of blank space, and only to divide blocks visually. Be concise with blank space. A minimum of blank space helps keep the spreadsheet on fewer screens, and helps avoid an impression of hidden or misplaced information. But most importantly, make blank cells look blank and make active cells look full. A cell's contents should appear in that cell visually.

Here, the labels in A1 and H1 run over into the next cell, but we can reasonably assume that they are left justified.

If you are very careful with blank, and you have an especially simple layout, you can drop the grid without frightening your reader. But be warned - warts like the wide “Wednesday” column here, show up more easily.