Statistics and Trace Evidence: The Tyranny of Numbers

By Houck, Max M. | Forensic Science Communications, October 1999 | Go to article overview
Save to active project

Statistics and Trace Evidence: The Tyranny of Numbers


Houck, Max M., Forensic Science Communications


Abstract

The public perception of science allies it closely with mathematics, and the application of statistics to forensic DNA analysis has reinforced this perception. Numbers, however, are not required for the scientific process. All science, including forensic science, is a method of understanding the world around us, and quantitation is only one tool to assist that methodology. Yet, the public and the courts expect forensic scientists, including trace evidence examiners, to use mathematics and statistics regularly, based largely on the DNA model. Recent articles and court rulings have even suggested that without statistics, trace evidence may not be acceptably scientific.

This expectation is fraught with pitfalls that could adversely affect the accuracy of evidentiary reports presented in court. The foundational data upon which trace evidence statistics might be based differ radically from those used in DNA statistical calculations. If statistics are to be applied to trace evidence, they must be applied in a way appropriate to the discipline, unbiased in interpretation, and accessible to the trier of fact.

DNA Analysis = Forensic Science

You might not expect an article on trace evidence to begin by discussing DNA, but the advent of forensic DNA analysis has produced significant changes in the perception, both public and professional, of forensic science. This is particularly true of trace evidence, where numerous attempts at statistical evaluation or data gathering have been published (Home and Dudley 1980; Biermann and Grieve 1996a, 1996b; Biermann and Grieve 1998; Curran et al. 1998). No one model has been widely adopted, particularly in the United States, and yet legal experts, attorneys, and the courts are increasingly interested in using statistical methods to increase the reliability of trace evidence. The comments most often heard by trace analysts, "Why can't you calculate a number like DNA?", and "Trace evidence is only 'could have' evidence," adequately frame the dilemma we face. We cannot provide the same statistical frequencies as our DNA colleagues, but we have observed that a positive association of paint, hair, or fibers is a significant event that is not likely to be duplicated at random. So, then, if trace evidence analysts know this, why can't they use statistics to help convey this information to the jury?

How Do We Know All Ravens Are Black?

Science has the ancient philosophical traditions of Greece, Rome, and the Middle East as its basis. The Greek philosophers, beginning with the mathematician Thales (ca. 600 B.C.) and including Aristotle (384-322 B.C.), were primarily rationalists, proposing the solutions to scientific questions by focused reasoning, what we now call deduction. Thales in particular was adamant in accepting only results that had been established by mathematical reasoning. Because all mathematical proofs are by their nature deductive (Kline 1967), this, along with other social factors in ancient Greek civilization, led to an inescapable reliance on deductive logic. The success of these ancient scholars in their explanations led to "an overrating of a purely rational approach" (Mayr 1982), reaching its pinnacle with the French philosopher and mathematician Rene Descartes (1596-1650). Like Thales, Descartes' ideal of scientific reasoning was a mathematical proof. This perception persists even today, particularly in the popular concept of science. It has persisted not only in the physical sciences, where mathematical proofs are often possible, but also in the biological sciences (Mayr 1982). The "tyranny of numbers," the trenchant belief that science is best expressed through mathematics, overshadows the potential explanatory power many disciplines have, simply because a mathematical value is expected but may not be possible. The Scottish historian David Hume (1711-1776) noted, for example, that in many, if not the majority of cases, it is impossible for biologists to provide proofs of pure mathematical certainty because of the complex nature of living systems (Hemple 1966).

The rest of this article is only available to active members of Questia

Sign up now for a free, 1-day trial and receive full access to:

  • Questia's entire collection
  • Automatic bibliography creation
  • More helpful research tools like notes, citations, and highlights
  • Ad-free environment

Already a member? Log in now.

Notes for this article

Add a new note
If you are trying to select text to create highlights or citations, remember that you must now click or tap on the first word, and then click or tap on the last word.
One moment ...
Project items

Items saved from this article

This article has been saved
Highlights (0)
Some of your highlights are legacy items.

Highlights saved before July 30, 2012 will not be displayed on their respective source pages.

You can easily re-create the highlights by opening the book page or article, selecting the text, and clicking “Highlight.”

Citations (0)
Some of your citations are legacy items.

Any citation created before July 30, 2012 will labeled as a “Cited page.” New citations will be saved as cited passages, pages or articles.

We also added the ability to view new citations from your projects or the book or article where you created them.

Notes (0)
Bookmarks (0)

You have no saved items from this article

Project items include:
  • Saved book/article
  • Highlights
  • Quotes/citations
  • Notes
  • Bookmarks
Notes
Cite this article

Cited article

Style
Citations are available only to our active members.
Sign up now to cite pages or passages in MLA, APA and Chicago citation styles.

(Einhorn, 1992, p. 25)

(Einhorn 25)

1

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Cited article

Statistics and Trace Evidence: The Tyranny of Numbers
Settings

Settings

Typeface
Text size Smaller Larger
Search within

Search within this article

Look up

Look up a word

  • Dictionary
  • Thesaurus
Please submit a word or phrase above.
Print this page

Print this page

Why can't I print more than one page at a time?

While we understand printed pages are helpful to our users, this limitation is necessary to help protect our publishers' copyrighted material and prevent its unlawful distribution. We are sorry for any inconvenience.
Full screen

matching results for page

Cited passage

Style
Citations are available only to our active members.
Sign up now to cite pages or passages in MLA, APA and Chicago citation styles.

"Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn, 1992, p. 25).

"Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

"Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences."1

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Cited passage

Welcome to the new Questia Reader

The Questia Reader has been updated to provide you with an even better online reading experience.  It is now 100% Responsive, which means you can read our books and articles on any sized device you wish.  All of your favorite tools like notes, highlights, and citations are still here, but the way you select text has been updated to be easier to use, especially on touchscreen devices.  Here's how:

1. Click or tap the first word you want to select.
2. Click or tap the last word you want to select.

OK, got it!

Thanks for trying Questia!

Please continue trying out our research tools, but please note, full functionality is available only to our active members.

Your work will be lost once you leave this Web page.

For full access in an ad-free environment, sign up now for a FREE, 1-day trial.

Already a member? Log in now.