1. Credibility of Evidence
Critical Thinking
Unit 1 – Introduction to Critical Thinking
Chapter 5
D Gray
September 2009
For the activities decide on solo, pair or group work in lesson.

2. Credibility of Evidence
Starter:
Write down at least five ways in which you would assess the credibility of a piece of evidence, such as a newspaper article on corruption in sport.
Rank them from best to worst.
Justify why your top answer is the best way to assess credibility
Justify why your bottom answer is the worst way to assess credibility
(5 mins)

3. Credibility of Evidence
Lesson Objectives:
To know and understand the meaning of the nine credibility criteria
To be able to apply the credibility criteria to a piece of evidence.
To be able to assess the credibility of a piece of evidence.

4. Arguments
Critical thinking teaches the skills required to analyse and evaluate arguments.
An argument is a reason or reasons which support a conclusion.
Evidence or examples are used to support reasons and conclusions.

5. Credibility of Evidence
Evidence and/or examples alone are not enough.
We need to judge the credibility of the evidence.
Credible means believable
Plausible means reasonable
Plausibility is whether or not a claim or piece of evidence is reasonable.
A Claim is a statement or judgement that could be challenged.
So, how do we measure credibility?

6. Claims & Plausability
Read and make notes on page 65 then do Activity 24 on Page 66
Read and make notes on Pages 66 – 69 then do Activity 25 on Page 70

7. Simple Ways of Assessing the Credibility of Evidence
What is the source of the evidence?
Where does it come from?
Who does it come from?
Is the source reputable?

8. Witnesses and Sources
Source – A person, organisation or document providing information or evidence.
Witness Statement – A report by someone who has actually seen (or heard) an event.
Criteria – Standards, measures or benchmarks, against which something can be measured.
The singular of criteria is criterion

9. Assessing the Credibility of Evidence
There are certain criteria we use in Critical Thinking to assess the credibility of evidence.
You must use these Credibility Criteria and the technical language associated with them in your exam.
You must learn them and use them all!!

10. Credibility Criteria Read and make notes on Page 71
Now read the passage on Pages 72 & 73.
In groups of 3 or 4 decide whether you would believe Andrew Atkins if he tried to sell you a quality car which will give you years of trouble free motoring.
Write down why and prepare to present to the class.

11. Assessing Credibility of Evidence
In pairs write a brief definition, in your own words, of what is meant by each of the nine credibility criteria.
Neutrality
Vested Interest
Bias
Expertise
Reputation
Ability to Perceive
Corroboration
Context
Consistency and Inconsistency
In addition to these also address Selectivity and Representativeness
(5 mins)

12. Ability to Perceive
Eyewitness evidence is generally better than hearsay.
Descriptions of events change when they are told.
Is the witness a reliable witness? Are they blind? Deaf? Biased? Have a vested interest?

13. Ability to Perceive
Read and make notes on Pages 74 & 75 then complete Activity 26 on Page 75.
Now do the ‘Take it further’ on Page 75

14. Assessing Credibility of Evidence
Corroboration
Evidence which supports other evidence.
Corroboration strengthens the credibility of evidence.
Is Fred guilty?
Fred was caught on CCTV stealing the jumper.
He was wearing it when found by the police.
The shop assistant saw him leaving the shop with it.
His fingerprints where on the display where the jumper went missing.
He was overheard boasting that he had stolen it to his friend 10 mins before being arrested.
Fred has 134 convictions for shop lifting.
Fred’s flat was found to be full of stolen property.

15. Corroboration
Page 76 Activity 27

16. Consistency and Inconsistency
Inconsistency is where two claims oppose each other – they can not be true at the same time.
Consistency strengthens an argument.

17. Consistency and Inconsistency
Page 76 Activity 28

18. Assessing Credibility of Evidence
Bias
Vested interests can lead to bias.
Bias means favouring a particular view or having a preference.
Bias can be very similar to loyalty.
A biased viewpoint can reduce the credibility of evidence.
Example: Everton will win because they are the best team in the land.

19. Bias
Page 77 Activity 29

20. Assessing Credibility of Evidence
Neutrality
A neutral source is impartial – it does not take sides.
Neutral sources have no motive to lie or to distort evidence.
Neutral sources have no bias.
If someone is neutral then it strengthens the credibility of their evidence.
Examples: ACAS, Rugby referees, Judges.

21. Neutrality
Page 78 Activity 30

22. Assessing Credibility of Evidence
Vested Interest
Does the person have something to gain from their version of the argument?
Have they lied?
Have they presented all the facts?
Have they been selective with their evidence?
If someone has a vested interest it can affect the credibility of their evidence.
Examples: Football managers, tobacco companies, Advertising companies.

23. Vested Interest
Page 78 Activity 31

24. Assessing Credibility of Evidence
Expertise
Evidence which is given by an expert can be judged as being very credible.
Be careful though that the ‘expert’ is a credible expert on what they are actually commenting on.
Is their evidence relevant?
Is it up to date?
Could they have made a mistake?
Are they biased?
Do they have a vested interest?

25. Expertise or Experience of Source
Activity 32 on Page 79

26. Assessing Credibility of Evidence
Reputation
Character
Professional standing
Altruistic
Are they fair, decent, honest?
Or are they motivated by self-interest, greed, desire, fame?
Examples: Broadsheets vs. tabloids
BBC news vs. Heat magazine

27. Reputation
Page 81 & 82 Activity 33

28. Assessing Credibility of Evidence
Context
Factors which can affect credibility of evidence
Was it night time? Foggy? Poorly lit?
Is there an atmosphere of fear?
Is the evidence historical? Is it out of date?
Does the evidence refer to the specifics of the argument?

29. Assessing Credibility of Evidence
Selectivity and Representativeness
Selecting and using evidence which only supports your conclusion.
Is ‘evidence’ only taken from a selected sample of the population?
Does the evidence represent the true views of the population?
Being selective reduces the credibility of evidence

30. Exam style questions
Page 83 – 85 Activities 33, 34 & 35.

31. And finally … Did we achieve the lesson objectives?
Do you understand what an argument is?
What is evidence?
How do we assess evidence?
What are the nine credibility criteria?
(5 mins)
Homework: Learn the nine credibility criteria for a test tomorrow!

32. Credibility of Evidence
Lesson Objectives review:
To understand how a basic argument is structured.
To know and understand the meaning of the nine credibility criteria
To be able to apply the credibility criteria to a piece of evidence.
To be able to assess the credibility of a piece of evidence.

33. Credibility of Evidence
Critical Thinking
Unit 1 – Introduction to Critical Thinking
Chapter 5
D Gray
September 2009
For the activities decide on solo, pair or group work in lesson.

34. Assessing Credibility of Evidence
It’s Just Not Cricket!
In groups of four, read the article on ‘It’s Just Not Cricket’.
Identify where the credibility criteria could be applied to the article.
Extension: Assess whether or not Hair acted honourably.
(10 mins)
Hair is a white Australian male.

35. It’s Just Not Cricket! Answers
Speed’s reputation is solid enough. As the Chief Executive of the ICC, he certainly has high status; he is in an important position of trust. This lends credibility to his claim.
His ability to see is more limited; it’s difficult for him to tell what was going on in Hair’s head. Yes, he had access to the correspondence, but he admitted in the press conference that this could be read in either of two ways. Unless he had private correspondence or conversations with Hair in addition to the published s, then his access to the evidence is the same as everyone else’s, and so he is basing his interpretation of events on background knowledge rather than clear first-hand evidence.
Speed certainly suffers from a vested interest. As someone with a great deal invested in cricket, and whose responsibility it is to protect the sport. He has a lot to lose if the reputation of cricket is damaged. This certainly weakens his sympathetic interpretation of Hair’s actions.

36. It’s Just Not Cricket! Answers
Speed’s level of expertise is a little difficult to assess. In this context, expertise would involve knowledge of Hair. Is Hair the type of person who would try to make money out of a potential disaster? Without better knowledge of the relationship between the two, it’s impossible to tell whether Speed possesses this expertise.
Finally, there is the issue of neutrality, which is again difficult to assess. If Speed and Hair have had a long and productive professional relationship, as may well be the case, then Speed may well have a bias towards Hair, and so a reason to defend him. If, on the other hand, they have no such rapport, or even a disliking for each other, then things may be different.
To reach an overall judgment on the credibility of Speed’s claim his reputation and possible expertise must be weighed against his poor ability to see, vested interest, and possible bias.
What is your judgment?