Critical Thinking
Credibility of Evidence 1
• Criteria to use (Criterion singular)
 Reputation-Does the source have a reputation for reliability,
e.g. the difference between The Sun and the BBC
 Ability to observe-Could the source see what it claims has
happened
 Vested Interest-Does the source have a reason to be biased
e.g. someone accused of war crimes who denies any responsibility
 Neutrality-Opposite of Vested Interest, does the source have a
neutral outlook on the claim
 Expertise/Training-Does the source have relevant training
or expertise that would support their claim, e.g. a Doctor giving a
medical opinion
Credibility of Sources
• Do you believe the source?
• Can you trust the claims being made?
Evaluation
•
•
•
•
•
Reputation
Ability to See
Vested Interest
Expertise
Neutrality / Bias
RAVEN
Reputation
• What is the track record of the witness?
• What is the status of the witness?
Reputation
•
TRACK RECORD - If a person has told lies in the past, then we will be less
trusting of them in the future … …Remember the boy who cried wolf?
•
STATUS - If a person is in a position of authority, like a judge or a professor, then
their status suggests that they can be trusted, as they need to be trustworthy to
do that job.
Whose reputation would you trust?
Job
Politician
Doctor
Used car
salesman
Teacher
√ or X
Reasoning
Ability to See
• Were they there to witness what happened?
• Did they have a clear view of what
happened?
Ability to See
A person who can see an event happening is
more reliable than someone who did not see
the event.
Use of other senses?
Sense
Sight
Hearing
Smell
Taste
Touch
How could this affect a witness’s evidence?
Vested Interest
• Does the witness have something to gain by
telling the truth?
• Does the witness have something to gain by
telling lies?
Vested Interest
• Vested Interest is when somebody might have
something to gain by lying about something…
• A plumber might look at a faulty washing
machine and say there is more wrong with it
than there really is…So that they can get
more work and make more money!
I can fix it…… …..
but it will cost
you!
Vested Interest
If somebody has a vested interest, then the
credibility of their evidence is weakened, and
therefore they are not as trustworthy.
Match the situation with the vested interest
I’m refereeing
an important
rugby match
I’m being
bullied at
school
I’ve been
accused of
shoplifting
I don’t want to have a
criminal record, so I’ll say
it wasn’t me
I’ve been offered £500 to
make sure Saracens win
the match
I daren’t tell anyone so I’m
going to keep my mouth
shut
Expertise
• Does the witness know what they are talking
about?
• Is their expertise relevant?
Expertise
• This doesn’t mean that somebody has to be
an expert to give evidence, but somebody
who knows what they are talking about is
more trustworthy than someone who
doesn’t.
• Expertise relates to whether an observer has
the right background knowledge to give
evidence on a subject.
Does the witness have expertise?
A traffic accident has occurred and the following
witnesses come forward to give their account
Learner
Driver
Traffic
Policeman
Primary
School Child
Jenson
Button
Motor
Mechanic
Neutrality / Bias
• Is the witness merely a neutral observer?
• Or does the witness have reason to favour
one particular side of a dispute?
Neutrality / Bias
• A neutral witness is somebody that doesn’t
take a side on the argument. If a person is
neutral, they are not influenced either way.
• The opposite of neutrality is Bias. If a person
is biased, they have already made their mind
up about a situation.
Bias In War Reporting
We:
They:
Our boys are:
Theirs are:
Take out
Destroy
Professional
Brainwashed
Suppress
Destroy
Cautious
Cowardly
Eliminate
Kill
Heroes
Cornered
Neutralise
Kill
Loyal
Blindly Obedient
Dig in
Cower in foxholes
Brave
Fanatical
We have:
They have:
Our leader is:
Theirs is:
Army, Navy, RAF
A war machine
Resolute
Defiant
Reporting Guidelines
Censorship
Statesmanlike
An evil tyrant
Press Briefings
Propaganda
Assured
A crackpot monster
Critical Thinking
Credibility of Evidence 2
• Criteria to use (Criterion singular)
 Nature of the claim-Is the claim itself credible, or very
unlikely, e.g. when someone claims to have witnessed a miracle
 Credible reasons for the claim-Can the source support
their claim with credible reasons, or is it not supported
 Corroboration-Is there corroboration of the claim from
independent sources, e.g. it is backed up elsewhere
You need to be able to use the Criteria in
deciding which sources and authorities are
credible/reliable and on what grounds
Using Credibility Criteria
When assessing the credibility of a source you should use
whatever criteria you think is relevant, and often will use at
least two.
EG – An Eye Witness Report Emphasis on the high credibility of direct
observation
But also
 Vested Interest – Did the eyewitness have anything to gain by including or
excluding evidence
 Bias – Did the eyewitness observe a friend and try to present them in the best
light?
 Expertise – Did the eyewitness have any relevant expertise which may
increase the credibility of the evidence
 Reputation – Has the eyewitness got a reputation for honesty or dishonesty
 Corroboration – Is the evidence given by the eyewitness supported by other
sources of evidence
 Selectivity – Did the eyewitness see only part of the event?
 Context – Did the context allow for a clear view of the event?
Here we can see combining different criteria improves our
assessment of credibility of evidence
Key Terms
Argument – A reason or reasons that support a conclusion
Evidence – Information used to support an argument
Source – Where evidence comes from e.g. eye witness
Credibility – Believability, a cr4edable source is a believable source
Credibility Criteria – criteria used to assess the credibility of sources
and evidence
Neutrality – Impartial, not taking sides
Vested Interest – Having something to gain from a particular outcome
Bias – Favouring a particular view
Expertise – Specialist knowledge
Reputation – What is generally thought about a person’s character or
Standing
Observation – Direct observation of an event by an eyewitness
Eye witness account – A report by someone who has personally observed
an event
Corroboration – Confirming, giving support to, Corroborative evidence is
evidence that supports each other, point in the same direction.
Selectivity – The choice of evidence to support an argument
Context – The setting or situation in which evidence is produced
Truth – Something that is accurate or correct
Credibility of Evidence
Can we apply the criteria?
Objectives
To apply the
criteria to multiple
evidence to assess its
credibility
To make
judgements on the
evidence
To start to come to
conclusions based
on the evidence
Table for assessing Multiple Evidence
Evidence Letter
Criterion
applied
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Effect on credibility
Corroboration
with….
Table for assessing Multiple Evidence
Two Dogs Fighting
Evidence Letter
A
B
C
D
J
Criterion
applied
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Effect on credibility
Corroboration
with….