1.3  Writing or Speaking for Specific Audiences

As a scientist, you may find it challenging to present your work — or to explain scientific concepts in general — to a less specialized audience. More challenging still, however, is addressing a mixed audience of both specialists and nonspecialists. Here are specific tips for these two situations.

Whether you are addressing specialized or less specialized audience members, it is a good idea to convey early the motivation for the work you report so that they can relate to it — that is, you must bridge the gap between what they know or are interested in and what you will present. With nonspecialists, this gap is wider than with specialists. You might find it harder to convey the motivation for your work.

Nonspecialists lack comparison points. If you mention an absolute value, such as a power consumption of 5 mW, they might not know whether that is a small or a large amount for the device you describe, and they might not even know whether it is little or much in general. You can suggest that the power consumption is low or high by writing something like "as little as 5 mW" or "as much as 5 mW," but it is more helpful to provide the missing comparison point in the form of a relative value, as in "30 percent less than the most economical device to date" or "three times the average power consumption of devices of type X." Frequently, you can usefully combine an absolute value with a relative one, as in "5 mW, which is 30 percent less than . . . "

One type of comparison that is useful to all audiences but particularly to less specialized ones, including students, is the analogy. When you draw a parallel between a new concept you are trying to explain and one that is familiar to (or easily grasped by) the audience, you increase the probability that your audience will understand the concept and remember it. For example, you might say that the human genome encoded in DNA is like instructions stored in a library. The power of an analogy depends on how familiar the audience is with the comparison point (here, the library), and also on how consistently you can carry the analogy through your document or presentation. For example, if you can go on to meaningfully compare chromosomes to books in this library and genes to the pages in these books, then you have a more powerful analogy.

Nonspecialists also lack visual references; they cannot automatically picture what you are talking about. Visual material — appropriate for all audiences but crucial for nonspecialists — can include drawings and photographs. Drawings, which can abstract unnecessary details to focus on the essential idea, are best for conceptual explanations. In contrast, photographs, with their visual richness, give a better idea of what the "real thing" looks like. Thus, to explain a new chemical process, use a process flow diagram to discuss the flow of chemicals through the installation, but use a photograph of the pilot plant to provide a feel for size, appearance, and so on. Here, too, provide a comparison point for size, such as including a person in the photograph.