Defining and Presenting Data

When I was asked to prepare this lecture, it was suggested that I should talk about the presentation of data. I thought about that for some time, and I asked myself, What is data anyway? There is no real problem in listing raw data; you need merely record it accurately in a readable fashion employing some understandable system. But that had nothing to do with thepresentation of data. You only present data after you have ar-ranged it, analyzed it, studied it, and made some sense out of it. And why do you present it at all? Clearly you present the data in order to convince someone that your analysis, and the conclusions drawn from that analysis, are sound. What kind of data do you present in order to do this persuading? A great variety of kinds. Graphs are a form of data; so are maps; so are photographs, circuit diagrams, tables, questionnaire forms. Is there any way of de-scribing how best to present these? There is, I think, if you consider them all as forms of evidence. Once you conceive of them this way, you can begin to see what evidence, or data, to present, and how to present it. Now the minute you use the word evidence, most lawyers will think of Wigmore. No one who has read a legal tome can avoid the name John Hen-ry Wigmore, Dean Emeritus of the Law School of Northwestern University. Dean Wigmore’s numer-ous books on evidence are cited again and again in legal briefs. I am going to rely heavily on Dean Wig-more’s The Science of Judicial Proof in talking about evidence. Lest this seem rather remote from the problems of scientific and technical writing, let me add some ideas of Percy Bridgman from his book