Powerpoint

Presentations

Powerpoint may be a pattern or an anti-pattern depending how it is used.

While there are good arguments that powerpoint is intriniscally corrosive to effective communication (an anti-pattern), I have tried to stay somewhat out of the ongoing arguments about the merits/risks of using low resolution presentation tools like PowerPoint and assumed that we will be asked to use them and should aspire to make the most of it. I have gathered these suggestions under the assumption that what people put on slides they want the audience to be able to read, respond to and think about.

With that, let’s start with a short list that focuses on powerpoint as used in business meetings. Some factors that make reading projected slides difficult

1. Displaying from PowerPoint’s editing mode, rather than full screen mode (note that presenting a PDF from Acrobat should use full-sreen as well).
2. Relatively low resolution, compressed dynamic range, and loss of color fidelity on projection
3. Aspect ratio changes in projection
4. Icons and text labels on shared VC systems that overlap and cover content in the slide
5. Sunlight in the room

Common challenges

Text/background contrast: Text is not sufficiently different from background and so difficult to read. (e.g., green blue overlap not good when color resolution is not saturated, black and white would be better) Suggestion: Maintain sufficient contrast. Note: There are tools if you are unsure; http://snook.ca/technical/colour_contrast/colour.html. Suggestion: Use black background slides for protein models that are against black. Suggestion: If you use more than one text or graphy color, have most text with the best color contrast. Limit your palette to easy to read colors (black, red, white).

Text size: too small to read (including chart labels) Suggestion: insist that all text be at least 14 point (even text scanned in with a diagram and labels in figures).

Line spacing: Default in PowerPoint is too tight. Suggestion: Set line spacing to 1.1

Styled text: Using Bold all the time means you can not use it for emphasis. Suggestion: Use bold for emphasis, and italic for non-english or emphasis. Avoid underlines as they compete with baseline of the text and add noise. Note: Typeface rendering, especially bold, is often crowded in Windows

Hierarchical lists: Often the most important information is at the lowest level. And PowerPoint makes each sub-head smaller. This can result in the most important conclusion being the last and smallest thing on the slide. Suggestion: Do not make super-heads bigger than sub-heads in bulleted lists. Select the bounding text box and set all the text in the list to 18 point.

Bulleted lists: Unordered list don’t give enough information, a list of things is too weak. Suggestion: Try to make causal claims (A → B, or A + B → C) or minimally provide lists ranked in order of importance rather than unordered lists of bullets. Most of our problems are multi-variate and so we need to find ways to discuss, represent and interrogate that.

Grid prisons: Tabular data is often presented with each cell surrounded by lines. All that competing ink takes away from the information in the table. Suggestion: use light or no lines in a table. Swim lanes (alternate light background colors) can help the eye scan a line in a table. When you use them, have at least one background color in a table be white (or the slides background color). Confirm that text color contrast with swim lane is strong. Note: White grids can generate an illusion of spots if they are too wide. Note: Heat maps can be great, avoid a heavy grid, use light, thin separators (or none), instead

Color on slides: Color washes, shadowed boxes, chiclets, light 3-D… don’t render well on imperfect projection. Suggestion: Avoid uses of color that don’t add information. Most organization can be done with placement of light lines or boxes. If you do use boxes, make sure that they fit the text. Boxes should not cut into or touch the descenders (the portion of a letter that extends below the baseline of a font).

Timelines: Showing the dependencies and critical path can be a critical point of discussion. However, typical Gannt chart timelines can be information sparse, with very small text associated with events and long horizontal bars. Suggestion: print your timelines on large paper (e.g., 11x17 or bigger) and drive the discussion to the deadlines, dependencies, and critical fators. Avoid all unnecessary horizontal and vertical lines, and ornamentation (shadows, funky icons, colors) they distract. Use the biggest text you can fit, aim for legibility.

Color in graphs: Using only color to distinguish treatments in graphs (i.e. using the same shape marker for data in different treatments or classes and only distinguishing them by color). Implication: Color blind audience members or color compromised presentations (xerox, poor projectors, faxes) don’t retain the distinctions. Suggestion: Use shapes, line style AND color. Also use saturation rather than color for continous variable information (especially for continuous data). Don’t use color as sole differentiator (e.g., red, yellow, green circles), use shape and saturation. Suggestion: Xerox your slide in B&W or Fax it and see what distinctions get lost. Bonus suggestion: Use gray rather than black for axes on a graph. This helps the data pop as it doesn’t need to compete with the x- and y-axis.

Graph legends. Legends are often not organized to make it obvious which line corresponds to which treatment. Suggestion: Label lines directly to avoid eyes having to scan back and forth from a key that sits apart from the data. Suggestion: order the key in a way that corresponds to the responses that are found in the graph.

Repeating text: In labels or tables, writing the same word repeatedly becomes noise. Suggestion: Use a category to label multiple rows or columns as appropriate.

Missing text: Empty cells in a table can be difficult to parse. Suggestion: Distinguish between blank vs. “none” or “n/a” in tabular data.

Dashes: there are three kinds; hyphen, en dash, and em dash (-. –, —) Note: A dash is a punctuation mark that is similar to a hyphen or minus sign, but differs from both of these symbols primarily in length and function. The most common versions of the dash are the en dash (–) and the em dash (—), named for the length of a typeface’s lower-case n and upper-case M respectively. — http://en.wikipedia.org/wiki/Dash Note: strictly speaking there is also the minus sign for arithmetic.

Many variables: Tables with many variables can be difficult to sort through if you don’t give me a sense of the expected values. Suggestion: When showlng many variables indicate norms/targets to make context and comparison clear (see discussion for medical data at http://www.edwardtufte.com/bboard/q-and-a-fetch-msg?msg_id=0003mm).

Dead space: Too often slides with a lot of information are poorly organized leaving swaths of empty space while crowding information. Suggestion: Look at your slide’s overall layout. Do you have a crowding problem? Consider using a grid to organize the information. Sometime two column text can help you balance the slide. Suggestion: Use fewer words, more images and more, well-designed charts.

Ten Things to avoid

1. Dashes don’t make good bullets in front of other symbols.
2. Vertical text is often poorly rendered on MS Windows.
3. Many type faces per slide or presentation. Use one if you can, or two, if there is a good reason.
4. Borders/picture frames around graphs or images.
5. Crowded and overlapping text from footers.
6. Too many divisions on graph scales (rarely need more than six lines)
7. Roman Numerals. II scans close to III. Use arabic numbers (e.g., Phase 2).
8. Misspelled words.
9. Using the mouse pointer to direct people’s attention during a Webex or shared presentations.
10. Too much text on a slide. It is very difficult for the audience to read and listen simultaneously (assume that audience can read, no powerpoint karaoke).