Research in Health Services
Concept and Idea
Rajnish K Gupta
Professor of Cancer Studies
Slides
Aisling de Hooge
Research and Information officer
Cancer Services
Search and Literature
Hypothesis Rationale
Search and Literature Review
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In information retrieval systems, the match between
query and document is severely unbalanced due to
the huge difference in the sizes of query and
document.
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Strengthen the query with related knowledge such as
context semantics
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Context based search approach
• Conceptual paradigm for performing search in
context
e.g. IntelliZap system
Search and Literature Review
Knowing where to look
An overview of search engines
General Search Engines
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Google
http://www.google.com
Yahoo
http://www.yahoo.com
Askjeeves
http://www.askjeeves.com
All the Web
http://www.alltheweb.com
AOL
http://search.aol.com/
Hot Bot
http://www.hotbot.com
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Teoma
http://www.teoma.com
Alta vista
http://www.altavista.com
Gigablast
http://www.gigablast.com
Lycos
http://www.lycos.com
MSN
http://search.msn.com
Medical Search Engines
Google
http://www.google.com
Yahoo
http://www.yahoo.com
Askjeeves
http://www.askjeeves.com
All the Web
http://www.alltheweb.com
AOL
http://search.aol.com/
Hot Bot
http://www.hotbot.com
Teoma
http://www.teoma.com
Alta vista
http://www.altavista.com
Gigablast
http://www.gigablast.com
Lycos
http://www.lycos.com
MSN
http://search.msn.com
Medical Search Engines
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Health On The Net: MedHunt
http://www.hon.ch/MedHunt/
MedHunt uses both humans and web crawling to build its index of
medical information.
MedicineNet.com
http://www.medicinenet.com/script/main/hp.asp
Medical information contributed by over 50 doctors and health
professionals.
MedlinePlus
http://medlineplus.gov/
Medical information from the US National Library of Medicine and the US
National Institutes of Health.
OmniMedicalSearch.com
http://www.omnimedicalsearch.com/
Meta search major medical search engines and databases from this new
service.
WebMD
http://www.webmd.com/
Long-standing portal of health and medical information.
Science Search Engines
Health On The Net: MedHunt
http://www.hon.ch/MedHunt/
MedicineNet.com
http://www.medicinenet.com/script/main/hp.asp
MedlinePlus
http://medlineplus.gov/
OmniMedicalSearch.com
http://www.omnimedicalsearch.com/
WebMD
http://www.webmd.com/
Science Search Engines
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Biocrawler
http://www.biologie.de/
Directory and search engine for biological information.
Chemie.DE
http://www.chemie.de/
Directory and search engine for information about chemistry.
Scirus
http://www.scirus.com
Scirus combines a targeted crawler from FAST that focuses only on web
sites with scientific content.
Search4Science
http://www.search4science.com/
Search4Science is a search engine put together by scientists for
scientists. It shows -- if you enter simple keyword searches you're often
presented with related scientific terms to expand or limit your query.
SciSeek
http://www.sciseek.com/
SciSeek is a focused web directory created by human editors. It's a
useful tool for browsing for information in a specific scientific area.
Other websites
Biocrawler
http://www.biologie.de/
Chemie.DE
http://www.chemie.de/
Scirus
http://www.scirus.com
Search4Science
http://www.search4science.com/
SciSeek
http://www.sciseek.com
Other Websites
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PubMed
http://www.ncbi.nlm.nih.go
v/entrez/query.fcgi
World Health Organisation
http://www.who.int/en/
National Library of Medicine
http://www.nlm.nih.gov/nic
hsr/hsrsites.html
Health Finder
http://www.healthfinder.go
v/
Irish Health Research Board
http://www.hrb.ie/
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Health Web
http://healthweb.org/
Discovery
http://health.discovery.com/
Irish Health
http://www.irishhealth.com/
Health World Online
http://www.healthy.net/
VHI
http://www.vhihealthe.com/
Bupa
http://www.bupa.ie/
Irish Medical Organisation
http://www.imo.ie/
Hypothesis Rationale
Pub Med
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
World Health Organisation
http://www.who.int/en/
National Library of Medicine
http://www.nlm.nih.gov/nichsr/hsrsites.html
Health Finder
http://www.healthfinder.gov/
Irish Health Research Board
http://www.hrb.ie/
Health Web
http://healthweb.org/
Discovery
http://health.discovery.com/
Irish Health
http://www.irishhealth.com/
Health World Online
http://www.healthy.net/
VHI
http://www.vhihealthe.com/
BUPA
http://www.bupa.ie/
Irish Medical Organisation
http://www.imo.ie/
Hypothesis Rationale
Plato
Several levels of comprehension ranging from
those based purely on sensory impressions to
eventual understanding, through dialectic, of the
first principles or Eidos (Ideas, or Forms)
Plato
Whewell
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Natural Philosopher = Scientist
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Imprecise nature of Ideas, Forms.
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Modern physics can be tested by the emergence
of scientific methodology.
Thought alone can never approach reality unless
founded on fact.
Such facts, referred to as data (datum) are
derived from the observation of natural events
or, from carefully designed experiments and
executed interventions.
Fibonacci
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Liber Abaci – described the famous Fibonacci series
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The Divided Line simile superimposed
Data versus Doxa
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Plato - in his paradigm of the line, separated
knowledge (Episteme) from opinion or supposition
(Doxa)
• Doxa – derives purely from sensory impressions
i.e. from the appearance of things
• Pistis – direct experience results in belief
• Eikasia – impressions or illusions
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Plato’s message – knowledge cannot be based on
unsubstantiated belief or conjecture.
Science is driven by hypothesis
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A proposed explanation for a set of observations (data)
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The ability to use reason to create hypotheses goes
beyond mathematics
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Perhaps corresponds to Plato’s dialectic – ability to
reason
Science is driven by hypothesis
It is the testing of such hypotheses by seeking
additional data (re-search), experimentally
(where necessary), that distinguishes scientific
knowledge from beliefs that are not based on the
rational interpretation of factual information
Medical Treatment
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In the past – based on Doxa unsupported by data
e.g. purging, bleeding, trephining
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Successful prevention or treatment of disease does
not necessarily require detailed understanding of
the cause, or of therapeutic mechanisms.
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Empirical observations – provide raw material for
the development and testing of hypotheses
Medical Treatment
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Validity of a hypothesis is examined by making a
judgement as to whether the relevant data support
or refute it.
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Occasionally, the result of an experiment or trial,
designed to test a hypothesis is sufficiently obvious
– no further analysis required
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Since different informal observers may draw
different conclusions from the data set, Scientific
method - use of objective methods to measure the
degree of certainty, i.e., the probability, that a
hypothesis is correct is often required
The Art of Conjecturing
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Probability theory has become a critically important
branch of mathematics and is as important to the
design of clinical experiments involving human
subjects (clinical trials) as it is to the analysis of the
results obtained
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Foundations were laid by Blaise Pascal and Pierre
de Fermat in 1654, dealing with the mathematics of
games of chance e.g. Double six
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Jakob Bernoulli - “Bernoulli trial”, dichotomous
outcome e.g. tossing a coin
Clinical Trials
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Designed to test the value of a particular treatment
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Outcome can be dichotomous e.g. survival or death
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Usually more complex since there are many factors
(or variables) which determine response
Various characteristics
• Dependent
• Independent
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Mathematical approach – multivariate analyses
• Independent risk factors
• Predict prognosis, particular disease, with a particular
treatment
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Such information permits treatment decisions to be
made i.e. evidence based
Clinical Trials
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Probability theory calculate the number of
patients required
Power of a study: degree of certainty that the
difference between the interventions, if present,
would be detected, specifying the anticipated
difference and the degree of certainty required
Bernoulli’s Law of Large Numbers states that the
more trials that take place, the closer the
proportion of successes will be to the proportion
that applies to an individual trial
Quantification of risk
• Evolved from Pafnuty Chebyshev - observed value is
compared to the expected value ie. Relative risk
So, finally
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There is a proposal to offer coverage for a breast
cancer screening program to women aged 20-40
in your Health Board.
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Four statements from four randomized controlled
trials
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On the basis of each statement, you should
indicate if you agree to the implementation of a
breast screening program.
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Assume that the costs of each program are the
same, each result was deemed to be statistically
significant.
During a 7-year follow-up
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Program A reduced the death rate from
breast cancer by 33%
Program B produced an absolute
reduction in deaths from breast cancer of
0.06%
Program C increased the rate of survival
from breast cancer from 99.82 to 99.88%
Program D prevented one death from
breast cancer for every 1666 women
screened
Which program do you recommend?
Thank you