Transcript Slide 1

Week 1. Scientific method and
research methodology
PhD seminar
Dr. Felipe Orihuela-Espina
Contents
1. Scientific method
2. Research methodology
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Recommended readings
 A. Bundy et al., The Researchers Bible
 Keppel, G. “Design and analysis: A researcher's
handbook” (1991 -2004) 4th Ed.
 Bundy, A. “The Need for Hypotheses in Informatics”
 http://www.inf.ed.ac.uk/teaching/courses/irm/notes/hypothe
ses.html
 The scientific method:
 Cotton J and Sekula S. The Scientific Method

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http://www.physics.smu.edu/pseudo/SciMeth/
http://teacher.nsrl.rochester.edu/phy_labs/AppendixE/Appe
ndixE.html
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THE SCIENTIFIC METHOD
(CLASSIC)
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Scientific method
 In general, science aims at providing explanations
of phenomena observed in nature and society
 This explanation is offered in terms of relations
between an observed phenomena (effect) as a
consequence of its possible origin (cause).
 These relations are established by means of
experimentation following the scientific method.
 i.e. experiments are central to science
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Scientific method
 Purpose:
 To build a representation of the
world/nature/society that is
accurate, reliable, consistent and
not arbitrary
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Objectivism
 There exist an objective reality which is the
same for everyone [Cotton and Sekula].
 Reality exists as an absolute goal: facts are facts
regardless of feelings, desires, hopes or fears of
people. Ayn Rand, “mother” of objectivism
 “If your own private reality includes a law of
gravity that is different from Newton's, any
predictions you make with it are not going to
match reality.”
[http://www.physics.smu.edu/pseudo/SciMeth/]
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Objectivism
 There exist [unchanging] laws by which
the universe works [Cotton and Sekula]
 These laws can be discovered (not invented)
through experimentation
 These laws may however not be
deterministic; they might be stochastic.
 Unchanging does not mean static! This
becomes especially clear in social research
as society evolves with time.
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Scientific method
 Fact:
 A fact is an observation that has been confirmed
repeatedly and that for all practical purposes it is
accepted as true.
 Definition by the National Academy of Sciences
 "Everyone is entitled to his own opinion, but not
his own facts.”
 Daniel Patrick Moynihan (1927-2003), Senador de los
EEUU
 "Facts do not cease to exist because they are
ignored.“
 Aldous Huxley
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A brief (not exhaustive) history of the
scientific method
384-322 BC: Aristotelic
Empiricism
~700-1000. Arabs Ibn al-Haytham , Abū
Rayhān al-Bīrūnī and Ibn Sina Avicenna
among others develop different forms of
experimentation and quantification to
discriminate among competing theories
Roger Bacon
Aristoteles
1214-1294. Roger Bacon describes
the cycle of observation,
hypothesis, experimentation and
verification
1561–1626. Fracis Bacon
incorporates induction as a rational
method to reach causality
Galileo Galilei
1564-1642. Galileo uses mathematical
demonstration as a form to obtain valid
scientific results
Francis Bacon
1791-1867. Faraday demands intelectual honesty and
criticism from peer (peer review) together with
scrupulous documentation of experiments so that they
can be reproduced.
S XIX-XX. Several contributions from Hume
(inductive reasoning), Mill (knowledge based
on experience), Popper (necessity for
falsability), Peirce (scheme for hypothesis
testing and randomization)
Michael Faraday
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Scientific method
 The scientific method in a nutshell
1. Observation of a phenomenon
2. Formulation of a hypothesis or plausible
explanation of the phenomenon that might
explain the observations
3. To carry out an experiment altering the
conditions and measuring/observing the
phenomenon under the changing environment
4. Confirmation (or refutation) of the hypothesis
based on evidence (observations) collected
during the experimentation
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Scientific method
Figure from: [www.studyblue.com]
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Scientific method
 The scientific method reviewed:
1. Observation and description of a phenomenon
2. Formulation of a research hypothesis or plausible
explanation of the phenomenon to explain the
observations as a causal mechanism (induction)
 I really mean causal
1. Use the hypothesis to predict the existence or ocurrence of
other phenomena, or to quantify new observations
(deduction)
3. To carry out several experiments altering the
conditions and measuring/observing the
phenomenon under the changing environment
4. Confirmation (or refutation) of the hypothesis based
on evidence (observations) collected during the
experimentation
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Scientific method
¡YOU CAN’T DEMONSTRATE
THAT A HYPOTHESIS IS
CORRECT/TRUE!
 To have positive evidence supporting a hypothesis is not
equivalent to demonstrate a hypothesis, let alone to confirm a
fact.
 …with positive evdience you only increase your confidence in
the hypothesis
 The more experiments are made that result in evidence
supporting your hypothesis, the bigger certainty you have on
your hypothesis
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Scientific method
 The sicentific method is an effort:
 Collective of all scientists
 Individual research are unavoidably influence by
personal and cultural bias
 Standardized to minimize bias
 Consensus among the scientific community is a
central demand in empirical research
[SwanbornPG1996]
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Scientific method
 The scientific method is an effort:
 Dynamic (time)
 It is subject to continuous revision
 The hypothesis that has been hold across many
observations might still be refuted at any time by
new evidence (facts)
 "When the facts change, I change my mind. What do you
do, sir?"
 Atribuido a John Maynard Keynes
 Science is self-corrective
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Scientific method
 The scientific method is an effort:
 Critic and creative
 Critical thinking is capable of deciding whether an
statement is always true, partially true or false.
 Creative thinking permits developing unique and useful
ideas worth of consideration
 http://www.umich.edu/~elements/probsolv/strategy/crit-ncreat.htm
 Without these two thinkings we would be unable to
formulate a hypothesis nor to confirm/refute them
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Scientific method
 The scientific method is an effort:
 Skeptical
 It requires experimental evidence before doing or accepting
an statement
 …but it admits assumptions (lacking evidence) based on
previous knowledge about the phenomenon
 Skeptical does not mean denier (available evidence is never
enough)
 Trust is of utmost importance among scientist.
 In principle, you trust that others researchers are being honest
 …yet you have to test/review/challenge their evidence.
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From hypothesis to facts
Hypothesis
Model
Scientific
thoery
Law
Fact
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Scientific method
 “In science, you encounter the disturbing fact that, if your "point of
view" does not agree with reality as determined by experiment
through the scientific method, then your point of view is simply
wrong.”
 [Cotton y Sekula, http://www.physics.smu.edu/pseudo/SciMeth/]
 Having said that:
 It is acceptable that our point of view changes as sciences gathers more

reliable evidence
…but that change must be guided by evidence.
 If a established theory ( one that has passed many experiments) is in
disagreement with new evidence, the theory has to be reviewed maybe
even discarded as a description of reality
 It may still be valid within certain restrictions
 Classical example: Newton’s gravity laws.
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RESEARCH METHODOLOGY
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What is a thesis?
 A thesis is:
 Original (creative) and significant
 A record of research (so that it is reproducible)
 A critical survey
 Reviews existing work
 Discusses results in terms of current evidence
 The conclusion of a set of coherent experiments
for testing certain hypothesis about a certain
phenomenon of interest.
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What is a thesis?
 A good thesis includes:
 Who? – A phenomenon being studied
 What? – A clear message, hypothesis and/or
claim
 …and evidence for this
 Why? – A motivation and justification
 How? - Methodology
 When (time) and where (spatial)? – Constraints,
limitations and discussion
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Common pitfalls while doing a thesis
 Being too ambitiuos
 Stopping reading after an initial survey of
related work
 Think that there is no related work
 You simply have not search thorough enough
 Not believing in the significancy of the
research or overestimating its relevance
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Dos and Don’ts
 Your thesis is NOT a core-dump of all you know about
everything [BundyA2004]
 …also it is helpful to create your own vademecum
 Be concise and go straight to the point, yet giving enough
background to make it self-contained
 Your thesis hang together in a coherent manner
[BundyA2004]
 Acknowledge:

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
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Everyone that has helped
Every institution involved
Every funding source
Every other’s work – avoid plagiarism
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Becoming an expert on a topic
 Read literature (both strictly and loosely related, although to a different
depth)
 …then read more …and more …and a bit more
 …not yet there…
 Talk to people
 …that include experts (of course!) but also non-experts (they are usually very good at
spotting holes!)
 Get feedback as well as new ideas
 Clearly bound your research
 …and your experimentation
 Abstract vs concrete
 Too abstract and it is likely that you won’t deliver
 Too concrete and it is likely that the contribution is not significant
 Write/Give talks
 Explaining things to other people (whether orally or written) is a good way of realizing

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one own’s limitations
When you are a real expert you hardly ever need overusing jargon
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Some tips
 Keep (organised) record of everything;
 Notes of your ideas
 Notes on read papers
 Set up and results of your experiments, but also distractions,
artefacts, etc
 Documentation of programs and code (that is in computer
science)
 etc
 Focus on principles and foundations, not on implementation
and performance
 Never, ever delete a file/data
 Keep different versions
 This helps to remember, but also allows you to go back if
something goes wrong
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Some tips
 Read and write!
 For a good understanding, reading a paper once is often not
enough.
 It is fine to fail, and publish it
 It is research, so you may guess what’s going to happen, but
cannot be sure.
 Publishing bias may nevertheless make difficult to publish
negative results.
 Admit ignorance
 …make questions, even if you think: (i) the expert is going to
laugh at you, or (ii) what you are asking is obvious for everyone
else.
 “Quien pregunta es tonto 5 mins., quien no pregunta es tonto
toda la vida” Spanish saying
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THANKS, QUESTIONS?
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