# The Scientific Method in Theory and Practice

```					The Scientific Method in
Theory and Practice

Research & Technical Writing
Donald Winslow
22 January 2007
The scientific method is a powerful tool for
learning about the world, based on
observation and reason.
Other ways of knowing:
Faith
Intuition
Experience
Instinct
Imagination
Maybe others…
The Scientific Method in Theory
• Logical positivists (e.g., Carnap, Hempel)
– Knowledge derives from empiricism & reason.
– Only verifiable statements have meaning.
• Karl Popper
– Only falsifiable statements have meaning.
– Observations have alternative explanations.
– It is often easier to disprove than to prove.
Steps of the scientific method
• Observe patterns.
• Devise alternative hypotheses to explain.
• Derive predictions of hypotheses.
• Design a study to test predictions.
• Perform study, record observations,
evaluate whether predictions met.
• Revise hypothesis if necessary and
repeat.
Step one: observe patterns
• Example: Bean plants near chicken coop
produce more pods than those on the
other side of the garden.
Step 2: Devise hypotheses.
• Devise one or more alternative
hypotheses that may explain observed
patterns.
• This requires inductive reasoning. There is
no way to know at this point whether any
hypothesis is correct.
• Example:
– Nitrogen from manure increases growth.
– Phosphorus from manure increases growth.
Derive predictions of hypotheses.
• This involves deductive reasoning.
• Researcher should be certain that if the
hypothesis is true, the prediction will hold.
• Example: Bean plants provided with
supplementary nitrogen will produce more
pods.
• Alternatively: Bean plants provided with
supplementary phosphorus will produce
more pods.
Design study to test predictions.
• An experiment is a powerful study design in
which a system is manipulated in order to
observe results.
• Control group is treated exactly the same as
experimental group, except for the factor of
interest.
• Example: grow beans with supplementary
nitrogen, beans with supplementary phosphorus,
beans with both, beans with neither.
Step five: Perform study
Observe results.
Example: Beans with supplementary
nitrogen produced more pods than
controls, but beans with supplementary
phosphorus did not. Bean plants that
received both nitrogen and phosphorus did
better than any other treatment.
Pod productivity of bean plants

70
Number of pods per plant

60

50
40

30

20

10

0
N           P               N+P   C
Treatment
Evaluate predictions of hypotheses.
• Observation that bean plants treated with
nitrogen produced more pods is consistent
with nitrogen-limitation hypothesis.
• Observation that bean plants treated with
phosphorus did not produce more pods
falsifies phosphorus-limitation hypothesis.
• Observation that bean plants treated with
both N & P produced more pods than
those treated with only N…?
Revise or refine hypothesis
as needed.
• Nitrogen supplementation increases seed
productivity.
• Phosphorus supplementation increases
seed productivity only when there is
abundant nitrogen.
• Design a new study to test different
predictions of revised hypothesis.
Falsifiability and frequentism
• If science can only proceed through
falsifying hypotheses, how do we ever
prove anything?
• Devise a null hypothesis of no effect.
• Test null hypothesis.
• If the null hypothesis is falsified, the
alternative hypothesis (the explanation of
interest) is accepted.
Statistical hypothesis-testing
• Researchers would like to generalize
results to entire population of interest.
• Not possible to measure every individual.
• Measure random sample of individuals
from population.
• Draw conclusions about population from
sample.
• This is inductive (inferential) reasoning.
The Scientific Method in Practice
• Science as a social & political
phenomenon.
• Funding
• Peer Review
Scientists are social animals.
Social structure of scientists
•   Work in research groups
•   Apply for funds from funding agencies
•   Hire technicians to conduct studies
•   Present results at conferences
•   Publish findings in peer-reviewed journals
Research group at large university
•   Faculty member
•   One or more post-doctoral researchers
•   Lab and field technicians
•   Undergraduate students in research
classes
Research groups interact
with each other…
• Within supporting institution.
– (e.g. university, biotech company, research
station)
• At conferences and meetings of
professional societies.
• Through the process of peer review.
Resources needed by scientists:
• Institutional support
• Scientific literature
• Money for research
– Write grant proposals to funding agencies
• Human resources
Seeking funds for research
• Submit grant proposal to funding agency
• Agency reviews proposal and determines
if it is worthwhile—if the knowledge
potentially generated is valuable and if it is
likely the researchers will succeed.
• You will have the opportunity to write a
research proposal in this course!
Once funding is secured,
research group carries out study.
• Submit abstract to professional society to
present a talk or poster at a meeting.
• Write a manuscript to submit to refereed
journal.
• May also publish in books or conference
proceedings or government documents,
but main target venue is the professional
journal.
Types of scientific journals
•   Broad scope: Science, Nature
•   Moderate scope: JAMA, BioScience
•   Specialized: Conservation Biology
•   Very specialized: Bulletin of the Oklahoma
Ornithological Society.
Peer review process
• Authors submit manuscript to journal.
• Editor determines if content is appropriate.
• If so, editor sends manuscript to other
practicing scientists with similar interests.
• Reviewers read articles and send
• Editor rejects manuscript or accepts it with
suggested revisions.
Publication process
• Authors must usually revise a manuscript
one or more times before final acceptance
for publication.
• Revisions sent to editor; editor may return
for further revisions as necessary.
• Publishing company sends page proofs to
authors to check for errors.
• Authors send corrected proofs and journal
issue is published.
Obtaining grants and publishing
papers are vital for survival of
researchers.

“Publish or perish!” they say.
Next week:
• Library resources
• Study design
• Research proposals
Read Chapter 2 & Appendix 1 in Knisely.

Supplemental readings from Gustavii:
Chapters 1, 2, and 3

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