1. Assessing Evidence:
Credibility and Relevance

2. Essential Concepts in Critical Thinking
The nature and importance of evidence
Opinions
Facts Assertions
Theory
Testable
Hypothesis
(prediction)
Evidence

3. Evidence:
Facts
Observations
Experimental
results
Data that provides basis for a
point of view
RELIABLE
VALID
REPEATABLE
Assess the authorship and the nature of the source

4. Primary sources
‘Raw’, original materials
or source where ideas
and data was first
communicated
• Data from experiments
• Artefacts
• Peer reviewed journals
Secondary sources
Source that reuses
information from
primary sources
•
•
•
•
Books
Magazines
Documentaries
Blogs

5. It is well known that increases in age adversely affect visual, tactile, and kinesthetic sensory
functioning. For example, aging leads to significant deteriorations in visual acuity [1]–[3]
and tactile acuity [4]–[7]; it is also accompanied by increases in weight-discrimination
thresholds [8]. Interestingly, however, higher-level perceptual abilities are often not
significantly affected by increases in age. Older adults can discriminate three-dimensional
(3-D) object shape as well as younger adults for both the visual and haptic modalities [9].
(Extract from: Holmin JS, Norman JF (2012) Aging and Weight-Ratio Perception. PLoS ONE 7(10): e47701)
References
1. Donders FC (1864) Accommodation and refraction of the eye, with a preliminary essay on physiological dioptrics.
(W. D. Moore, Trans.). London: New Sydenham Society. 188–193.
2. Elliott DB, Yang KCH, Whitaker D (1995) Visual acuity changes throughout adulthood in normal, healthy eyes:
Seeing beyond 6/6. Optom Vis Sci 72: 186–191.
3. Pitts DG (1982) Visual acuity as a function of age. J Am Optom Assoc 53(2): 117–124.
4. Norman JF, Kappers AML, Beers AM, Scott AK, Norman H, et al. (2011) Aging and the haptic perception of 3D
surface shape. Atten Percept Psychophys 73: 908–918

6. Evidence:
Facts
Observations
Experimental
results
Data judged to be relevant to
the topic investigated
RELIABLE
VALID
ACCURATE & RELEVANT
Evaluate the information and its interpretation

7. Is the evidence ….
Accurate? Relevant? Representative?
“France is a rainy country. My aunt in Paris says it rains 360
days of the year. All the supermarkets sell umbrellas! I
visited my aunt last year and it rained the entire weekend I
was there.”

8. Authorship
Who says so?
Authority
Who is he/she?
Are his/her views
shared?
Accuracy
Provenance
Evaluating
evidence’s
credibility &
relevance
Is it accurate?
Is this a primary or a
secondary source?
Nature
Facts or opinions?
Context
When was it reported?
Is it focussed?
Is it representative?