Types of Evidence & Understanding Credibility

Margot Cooper Gruen

TYPES OF EVIDENCE &

UNDERSTANDING CREDIBILITY

Precedent EvidenceStatistical EvidenceTestimonial Evidence

Hearsay EvidenceCommon Knowledge Evidence

THERE ARE 5 TYPES OF EVIDENCE IN A CRITICAL THINKING CONTEXT:

Precedent evidence consists of two forms: legal and personal.

Legal precedent is the application of prior judicial decisions to new case. Precedents are generally rarely changed, due to the fact that it becomes a ‘standard’ in court and attempts to make judicial decisions uniform in nature.

The Ohio State Bar Association explains why judges follow precedent:

PRECEDENT EVIDENCE

Via: Ohio Bar

PERSONAL PRECEDENT IS MAKING INFERENCES BASED ON PAST RESULTS. FOR EXAMPLE, L IVING IN LOS ANGELES, YOU KNOW YOU

WILL MOST L IKELY GET A TICKET IF YOU PARK ILLEGALLY.

Via: Youtube

STATISTICAL EVIDENCE

Statistical Evidence is presented in the form of numerical facts. Although many people believe statistics to be infallible, this is far from the truth. Statistics can be misleading, because although they attempt to be objective, there are few cases where this is completely accurate. Scholar and professor at Augsburg College, Milo Schield wrote an article titled; “Statistical literacy: Thinking critically about statistics.” He mentions some key points regarding statistics and critical thinking. “Statistical literacy focuses on making decisions using statistics as evidence just as reading literacy focuses on using words as evidence. Statistical literacy is a competency just like reading, writing or speaking. Statistical literacy involves two reading skills: comprehension and interpretation.” He also goes on to discuss three important distinctions within the field of statistical evidence: association versus causation, sample versus population, and quality versus power of a test. It is shown by all of these factors that statistical evidence should be put under just as much scrutiny as any other type of evidence. 

SATIRICAL STATISTICS

Evolution favors female promiscuity. In a study of mouse-like marsupials, "survival of babies with promiscuous mothers was almost three times as high as those in the monogamous group." Key reasons: 1) "The sperm of some males were far more successful than others." 2) "Babies fathered by these males were twice as likely to survive." Takeaway for women: "Polyandry improves female lifetime fitness." Takeaway for men: "Males with more competitive ejaculates sire more viable offspring." Fine print:  "Males usually died after a short and intense single mating season due to exhaustion and aggressive encounters with other males." (Did we mention that female promiscuity promotes big testicles and small brains in males?) 

Via: Slate

An article by William Saletan on Slate.com lists some studies and their results with a satire edge. One of them:

TESTIMONIAL EVIDENCE

Testimonial evidence consists of a person’s testimony (opinion of reality). Generally when using evidence, it is preferable to put importance on provable facts rather than opinion or recollection. The three types of testimonial evidence are:

1.Eyewitness

2.Expert-witness

3.Historiography

EYEWITNESS

1. Eyewitness – person who saw something take place’s recollection. This type of evidence has inherent flaws, as everyone has a different ‘reality.’ In Problems and Materials on Trial Advocacy, authors Levin & Cramer discuss eyewitness testimony: 

“Eyewitness testimony is, at best, evidence of what the witness believes to have occurred. It may or may not tell

what actually happened. The familiar problems of perception, of gauging time, speed, height, weight, of accurate identification of persons accused of crime all contribute to making honest testimony something less

than completely credible.”

EXPERT-WITNESS

2. Expert-witness – This type of testimony is consists of declarations from people considered ‘professionals’ in a given field. Even within this type of testimony, professionals can disagree and are still subject to bias.  According to the Legal Information Institute, a group within Cornell Law School, the following are general rules for expert witness testimony:

HISTORIOGRAPHY

3. Historiography – This testimony is presented by a historian. In the article “The Historian’s Valuable Role as Expert and Advisor in Environmental Litigation” authors state: 

“Retaining a professional historian as an expert witness, can be useful in avoiding the limited

perspective and fading memories of eyewitnesses and the perception of bias associated with advocates relating historical facts. Historian experts, similar to

their counterparts in the hard sciences, employ specialized contextual knowledge and a disciplined

methodology in their research and analysis, and use a customized and targeted approach to effectively

gather and synthesize the available historical evidence and to relate historical facts in a thorough

and compelling manner.” 

HEARSAY EVIDENCE

Hearsay Evidence consists of rumors or gossip that are repeated among multiple people. This type of evidence is mostly used in non-formal arguments, when lack of other types of evidence are present. Hearsay can also be used to determine motives, or at least open the door to some ideas.

The clip on the next slide from The Daily Show with Jon Stewart provides an example of the ‘powerful’ evidence of hearsay, tied into a news story about school curriculums and race:

Via: The Daily Show

COMMON KNOWLEDGE EVIDENCE

Common Knowledge Evidence consists of using information that is readily accepted by (mostly) everyone. This information is generally uncontested, so it is most useful in non-confrontational or non-controversial arguments.

With all the diff erent types of evidence that can be presented to make a case or claim, it is crucial that as a critical thinker, the credibility of evidence presented is evaluated closely. As outlined with each type of evidence, there is the possibility for fault many steps of the way.

Critical thinkers should strive to develop skills that question information. Carl Sagan, an astronomer and scientist, is quoted, “Extraordinary claims require extraordinary evidence.” He also explained that critical thinkers need be skeptical, but also open minded.

The next slides outline a speech by Sagan that examines the balance required between skepticism and open-mindedness:

CREDIBILITY

It seems to me what is called for is an exquisite balance between two confl icting needs: the most skeptical scrutiny of

all hypotheses that are served up to us and at the same time a great openness to new ideas. Obviously those two modes of thought are in some tension. But if you are able to exercise only one of these modes, whichever one it is, you’re in deep

trouble.

If you are only skeptical, then no new ideas make it through to you. You never learn anything new. You become a crotchety old person convinced that nonsense is ruling the world. (There is, of course, much data to support you.) But every now and then, maybe once in a hundred cases, a new idea turns out to be on the mark, valid and wonderful. If you are too much in the habit of being skeptical about everything, you are going to miss or resent it, and either way you will be standing in the way of

understanding and progress.

CARL SAGAN QUOTE

On the other hand, if you are open to the point of gullibility and have not an ounce of skeptical sense in

you, then you cannot distinguish the useful as from the worthless ones. If all ideas have equal validity then you are lost, because then, it seems to me, no ideas have

any validity at all.

Some ideas are better than others. The machinery for distinguishing them is an essential tool in dealing with the world and especially in dealing with the future. And

it is precisely the mix of these two modes of thought that is central to the success of science.

Via: Brain Pickings

CARL SAGAN QUOTE CONT.

Evaluating information consists of differentiating facts and opinions, recognizing generalizations and biased language.

Critical thinkers should be skeptical, question everything. The quality of information, the rationality of information, the biases and prejudices inherent in people, and the motive behind content presented.

EVALUATING AS A CRITICAL THINKER

“The essence of the independent mind lies not in what it thinks, but in how it thinks.”

― Christopher Hitchens, Letters to a Young Contrarian

QUOTES

A wise man proportions his belief to the evidence.

– David Hume

QUOTES

(Click to View)

LASTLY, A VIDEO FOR ARTISTIC PURPOSES OF SHOWING HOW EVIDENCE WAS

GATHERED FOR A STUDY IN DENMARK.

Reis, Michael C., and W. David Wiseman Jr. "The Historian’s Valuable Role as Expert and Advisor in Environmental Litigation." Environmental Litigator . 22.3 (2011): 12-14. Print. <http://www.historyassociates.com/wp-content/uploads/2012/06/HistoryAssociates_Historians_Role_As_Expert.pdf>.

Schield, Milo. "Statistical literacy: Thinking critically about statistics." Of Significance 1.1 (1999): 15-20.http://web.augsburg.edu/~schield/MiloPapers/984StatisticalLiteracy6.pdf

CITATIONS