Chapter 7 - EvidenceChapter 7 - Evidence

EvidenceEvidence

Evidence – the support for a claim that the Evidence – the support for a claim that the arguer discovers from experience or arguer discovers from experience or outside authority: examples, statistics and outside authority: examples, statistics and testimonytestimony– Sphere dependent on:Sphere dependent on:

What “counts”What “counts”

Most significantMost significant

Credible Sources?Credible Sources?

The OU PostThe OU Post

U.S. Department of Energy ReportU.S. Department of Energy Report

Journal of the American Medical Journal of the American Medical AssociationAssociation

Playboy MagazinePlayboy Magazine

EvidenceEvidence

ExamplesExamples

StatisticsStatistics

TestimonyTestimony

Principles for Using EvidencePrinciples for Using Evidence

Evaluating EvidenceEvaluating Evidence

ExamplesExamples

1) undeveloped instances used in an 1) undeveloped instances used in an argument by generalizationargument by generalization

– Ex. There are many benefits to getting an Ex. There are many benefits to getting an advanced degree: increased knowledge, advanced degree: increased knowledge, higher pay, more marketability to name a few.higher pay, more marketability to name a few.

ExamplesExamples

2) an extended instance that illustrates a 2) an extended instance that illustrates a general principle (also known as an general principle (also known as an illustration)illustration)

Ex.: What is it like to be homeless?Ex.: What is it like to be homeless?

Once you've been homeless, it's easy to explain. But when you’ve never Once you've been homeless, it's easy to explain. But when you’ve never

been out there on the street and stayed out there all night for months been out there on the street and stayed out there all night for months

and winters and summers and over and over and over…you don’t know and winters and summers and over and over and over…you don’t know

what it’s like to be out there. No money. Nowhere to stay. Nobody gonna what it’s like to be out there. No money. Nowhere to stay. Nobody gonna

feed you. You got nothing. And it’s cold as hell out there. Thirty-two feed you. You got nothing. And it’s cold as hell out there. Thirty-two

degrees. A big storm. Where you gonna go? Can’t go back to momma. degrees. A big storm. Where you gonna go? Can’t go back to momma.

Can’t go to you're girlfriend. I’m homeless. I’m cold. So cold you could Can’t go to you're girlfriend. I’m homeless. I’m cold. So cold you could

scream. The first thing is shelter. If you’re outside somewhere, you get scream. The first thing is shelter. If you’re outside somewhere, you get

frostbite. Get you something to eat. Get you a weapon. You don’t want to frostbite. Get you something to eat. Get you a weapon. You don’t want to

be homeless with no knife. Because you ain’t the only one out there be homeless with no knife. Because you ain’t the only one out there

homeless and the homeless feed off the homeless. You got a nice coat homeless and the homeless feed off the homeless. You got a nice coat

and you go to sleep? You wake up and I got your coat. You drink too and you go to sleep? You wake up and I got your coat. You drink too

much? I got your boots. That’s how they do it on the street. I’ve seen it much? I got your boots. That’s how they do it on the street. I’ve seen it

happen. I saw a guy damn near killed for his coat. They took the coat happen. I saw a guy damn near killed for his coat. They took the coat

and then they just started stabbing him. I say “Damn you got the coat. and then they just started stabbing him. I say “Damn you got the coat.

Why you stabbing the dude?” They left him for dead. It’s not nice out. Why you stabbing the dude?” They left him for dead. It’s not nice out.

It’s not nice being homeless. (Timothy)It’s not nice being homeless. (Timothy)

Examples continued…Examples continued…

Should have characteristics of good Should have characteristics of good storiesstories

Should ring true for audienceShould ring true for audience

Characters, motives, outcomes that make Characters, motives, outcomes that make sensesense

Real examples should be used whenever Real examples should be used whenever possible (limit hypothetical examples)possible (limit hypothetical examples)

StatisticsStatistics

Numerical compacting of examplesNumerical compacting of examples

Can talk about large number of examples Can talk about large number of examples without citing each onewithout citing each one– Raw NumbersRaw Numbers– Central tendenciesCentral tendencies– ProbabilitiesProbabilities– TrendsTrends

Raw NumbersRaw Numbers

Self-explanatory. Just the numbers.Self-explanatory. Just the numbers.– Ex. The United States Department of Defense Ex. The United States Department of Defense

FY 2007 base budget is $439.3 billion dollars FY 2007 base budget is $439.3 billion dollars ((www.whitehouse.gov).).

– In comparison, The United States Department In comparison, The United States Department of Education FY 2007 tentative budget is 54.4 of Education FY 2007 tentative budget is 54.4 billion dollars. (billion dollars. (www.ed.gov) + 9 billion dollars ) + 9 billion dollars in mandatory spending.in mandatory spending.

Central TendenciesCentral Tendencies

What is normal in a larger population. What is normal in a larger population. Often called averages.Often called averages.– Mean, Median, ModeMean, Median, Mode– Mean = average value across populationMean = average value across population– Median = middle numberMedian = middle number– Mode = most frequently occurring numberMode = most frequently occurring number

ProbabilityProbability

In terms of statistics, probability generally In terms of statistics, probability generally relates to frequency.relates to frequency.– Ex. Fibrodysplasia ossificans progressiva, or Ex. Fibrodysplasia ossificans progressiva, or

FOP, strikes about one in 2 million people — FOP, strikes about one in 2 million people — so rarely that most physicians misdiagnose so rarely that most physicians misdiagnose the disorder, often prescribing treatments that the disorder, often prescribing treatments that worsen the condition. About 600 patients are worsen the condition. About 600 patients are known.known.

TrendsTrends Compare a situation over time.Compare a situation over time.

TestimonyTestimony

Testimony is the statement of another Testimony is the statement of another person or agency used to support a claimperson or agency used to support a claim– Testimony of factTestimony of fact– Testimony of opinionTestimony of opinion

General PrinciplesGeneral Principles

Use representative instancesUse representative instances

Use a sufficient number of instances (Rule Use a sufficient number of instances (Rule of 3)of 3)

Account for negative instancesAccount for negative instances

Give the value characteristicsGive the value characteristics

General PrinciplesGeneral Principles

Use detailsUse details

Use current examples and statisticsUse current examples and statistics

Carefully consider statistical measuresCarefully consider statistical measures

Evaluating EvidenceEvaluating Evidence

ReliabilityReliability

ExpertiseExpertise

ObjectivityObjectivity

ConsistencyConsistency– ExternalExternal– InternalInternal

Evaluating EvidenceEvaluating Evidence

RecencyRecency

RelevanceRelevance

AccessAccess