Kỹ thuật ngẫu nhiên hóa câu trả lời (Randomized Response Technique)

Có những câu hỏi nhạy cảm và người ta không muốn trả lời trực tiếp, vậy thì làm thế nào. Kỹ thuật ngẫu nhiên hóa câu trả lời cho phép người trả lời được chọn, bằng việc quay đồng xu xấp ngửa, trả lời một câu không ‘nhạy cảm’ hoặc là một câu nhạy cảm (chính là câu ta muốn hỏi).

Ví dụ: Người được hỏi được đề nghị quay một đồng xu, nếu nó xấp thì trả lời câu

1) Ngày sinh của anh là tháng 9 hoặc tháng 10 phải không?

Nếu nó ngửa, thì trả lời câu 2

2) Anh đã bao giờ lái xe trong khi say rượu chưa?

Nhà nghiên cứu không được phép biết là người trả lời đã quay được xấp hay ngửa (tức là trả lời câu 1 hay 2) mà chỉ ghi lại số lần trả lời là ‘Có’ / ‘Đúng’

Ví dụ ta hỏi 36 người theo cách trên và thu được 12 câu trả lời ‘Có’ / ‘Đúng’. Vậy tỷ lệ người đã từng lái xe khi say rượu là bao nhiêu? Xem mô hình sau:

	Cơ chế dùng để xác định câu hỏi về ngày sinh hay là lái xe khi say rượu (tung đồng xu)     |   <______ 36 người được hỏi, có 12 câu trả lời Có/Đúng _____>   | Nếu đồng xu là cân và không có thiên lệch, một nửa số người sẽ chọn được câu về ngày sinh (36/2=18) Nếu đồng xu là cân và không có thiên lệch, một nửa số người sẽ chọn được câu về lái xe say rượu (36/2=18) | | 1 năm có 12 tháng, xác xuất để 1 người sinh tháng 9 hoặc 10 là 2/12 = 1/6. Do ta có 18 người, số người sinh vào tháng 9, 10 = 18x1/6= 3 ________.   Do số người trả lời ‘Có’/ ‘Đúng’ ở câu ngày sinh là 3, số người trả lời ‘Có’ / ‘Đúng’ ở câu lái xe say rượu là 12 – 3 =9 | Vậy tỷ lệ lái xe khi say rượu là 9/18 hay là 50% ở nhánh phải và 9/36 hay là 25% trên mẫu

Nhược điểm của kỹ thuật này: không xác định được trường hợp cụ thể nào là case, mà chỉ biết rằng hiện tượng đó có tỷ lệ là như thế.

Book Review: Substance Use and Abuse: Sociological Perspectives by Victor N. Shaw (2002)

Substance Use and Abuse: Sociological Perspectives by Victor N. Shaw
My rating: 2 of 5 stars

Not a bad one but it appears that only few people have read this book. Each chapter discusses a major sociological approach to substance use and abuse (alcohol, heroin, etc). Each chapter also offers ways of applying each theoretical perspective in research and practice. However, as a whole, the book lacks a sense of critique and that may not attract people who like discussing sociological theories.

View all my reviews

Fake Chinese malaria medicine sold in Vietnam ?

Scientists trace fake anti-malaria pills to dealer in southern China
--------------------------------------------------------------------------------
Scientists and police have struck back against the global menace of
counterfeit drugs in a unique collaboration that has led to the
seizure of hundreds of thousands of fake anti-malaria tablets and the
arrest of a key dealer in southern China.

In a stunning piece of forensic detective work, scientists who
analysed pollen grains and minerals in the fake drugs were able to
trace their origin to the Yunnan province of southern China, where
almost a half of all blister packs of the antimalarial drug
artesunate are thought to be fake.

The arrested dealer is alleged to have traded 240 000 blister packs
of fake artesunate, enough to "treat" almost 250 000 adults with a
medicine that has no effect on the potentially fatal disease. Chinese
authorities seized 24 000 of the blister packs but the remainder are
thought to have been sold on the border between Yunnan province and
Burma [Myanmar].

Details of the collaboration, called Operation Jupiter, are published
for the 1st time today [13 Feb 2008] in the online journal of the
Public Library of Science, PLoS Medicine [The research article on
PLoS Medicine available at:
<http://medicine.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.pmed.0050032>]. 

The investigation was co-ordinated by Interpol with the World Health
Organisation and scientists from the Wellcome Trust SE Asian Tropical
Research Programme at the University of Oxford.

The WHO estimates that fake drugs account for more than 10 percent of
the global medicines market but pharmaceutical companies are often
reluctant to admit they have fallen victim to the counterfeiters for
fear of damaging sales of the genuine product.

Paul Newton, who led the research, said fake anti-malarial drugs were
an increasing problem, especially in South-east Asia and Africa.
Malaria is widespread in Burma [Myanmar], Laos, Cambodia and Viet Nam
and up to half of all artesunate tablets in these regions are thought
to be counterfeit.

Dr Newton said: "Artesunate... is vital for malaria treatment and is
one of the most effective weapons we have against this terrible
scourge. Those who make fake anti-malarials have killed with
impunity, directly through the criminal production of a medicine
lacking active ingredients and by encouraging drug resistance to
spread. If malaria becomes resistant to artesunate the effect on
public health in the tropics will be catastrophic."

Fear about growing drug resistance have been raised because some fake
drugs seized in Operation Jupiter turned out to include dangerously
small quantities of artesunate, probably in an attempt to foil
screening tests implemented as quality checks. The doses included
were too low to tackle the disease but high enough to contribute to
the malaria parasites acquiring resistance to the drugs.

Most of the seized drugs contained no artesunate or a wide range of
potentially toxic ingredients. The scientists who analysed the drugs
used a sophisticated technique called forensic palynology to study
pollen contamination in the samples, from which they were able to
track the likely location of manufacture.

The pollen evidence suggested at least some of the counterfeit
artesunate came from southern China and this was backed up by
examination of the mineral, calcite, also found in some samples.
Scientists from 5 laboratories were involved in analysing the fake
drugs and their packaging.

Dr. Newton said the success of Operation Jupiter proved it was
possible to help countries facing a major threat from counterfeit
drugs. "Criminal investigations and legal action are important in
disrupting and inhibiting the trade in fake medicines, but to be
effective these will require financial support and resources," he
said. "Forensic tools may make it easier to identify the fake drugs
and allow over-stretched police forces to focus on objective leads,
greatly increasing the risks to counterfeiters of being caught."

"But there are very few laboratories with the resources to perform
detailed forensic chemistry or pollen analysis of fakes, particularly
in the countries where they are most needed."

Full story

Health issues in Vietnam from WHO perspective!

Viet Nam

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10000
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RISK FACTORS

- Chronic diseases
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HEALTH SYSTEMS

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INEQUITIES IN CHILD HEALTH (DIFFERENTIALS)

- Child mortality
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WHO | Viet Nam