• Clayton T. Robertson

The Absence of Evidence Is Evidence

By Clayton T. Robertson (Criminal Defense / Civil Litigation Attorney)

There is a saying that the "absence of evidence is evidence."

As humans, we are accustomed to look for "positive cues" -- i.e., what do we see in front of us? An equally valid, and sometimes more appropriate technique, is to look for "negative cues" - i.e., what is missing and why does that missing element have meaning? For example, on a topic on which I love to blog, with respect to reading a person's body language, often it is not the presence of a cue, but its absence that matters.

In civil litigation, the technique of looking for what doesn't exist (when it should if something were true) is called "negative spacing." This technique of questioning a witness about what they didn't observe or didn't do, when it should have been seen or present, can be used in depositions or the cross examination of experts. It may also be used in criminal defense when we cross examine officers and prosecution experts. We may also apply this technique when we investigate our cases, both in criminal defense and civil litigation. During our investigation, we should look for not only what is present, but what is absent, when we speak with witnesses, review documents, inspect physical evidence, or examine the scene of an incident. Finally, when we develop a theory of the case -- i.e., how or why it happened in a way that supports our client's version of events -- it is crucial that both positive and negative cues support it.

I recently read an excellent description of this topic from a well-known social psychologist who has written extensively on the topic of persuasion. He uses a comparison to Sherlock Holmes, which I have done in a prior blog ( In the excerpt below, taken from Pre-Suasion: A Revolutionary Way to Influence and Persuade by Robert B. Cialdini, no better description of this topic likely exists.

"There’s a very human reason for why you’d be prone to fall for my trick. Its obtuse scientific name is “positive test strategy.” But it comes down to this: in deciding whether a possibility is correct, people typically look for hits rather than misses; for confirmations of the idea rather than for disconfirmations. It is easier to register the presence of something than its absence. The great mystery novelist Sir Arthur Conan Doyle understood this tendency in crafting the anything but ordinary thinking style of Sherlock Holmes. The brilliant Holmes was as unrelenting in his attention to what didn’t occur as to what did. Recall that in one of Doyle’s most popular mystery stories, “Silver Blaze,” Holmes realizes that a theft under investigation is an inside job (and could not have been committed by the stranger police had under arrest) because during the crime a guard dog didn’t bark. His less intellectually disciplined counterparts, content to rely mainly on the presence rather than the absence of confirming evidence, never match his powers of deduction.”

Cialdini, Robert B.. Pre-Suasion: A Revolutionary Way to Influence and Persuade (pp. 22-23). Simon & Schuster. Kindle Edition.

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