The Scientific Method

For any controlled scientific study, a scientist starts with an observation, does some research to develop a hypothesis, and then designs an experiment that compares some baseline group with a test group. Data are then collected to confirm or refute the hypothesis.

As you review the following study, consider whether the researchers correctly followed the scientific method.

In the late 1990s, gastroenterologist Andrew Wakefield, along with a research team, set out to determine if bowel disease caused by vaccines led to autism.

He compiled a group of 12 children who had loss of acquired skills, developmental delays in language, diarrhea, and abdominal pain-essentially, those with both bowel disease and autism. He questioned each parent about the behavior and personality of the child before the child was vaccinated with the Measles, Mumps, and Rubella (MMR) vaccine. He then ran tests on the children to determine the health of the gastrointestinal tract, brain, and nervous system.

His reported data (tabulated below) included that children experienced either gastrointestinal or autism-like symptoms, sometimes within a short period after being vaccinated. From these data, the researchers concluded that there was no link between autism and the MMR vaccine. Wakefield though, contradicted this conclusion and stated that the vaccine caused changes in the gastrointestinal tract of the children, which then led to autism (Wakefield, et al., 1998). Currently, he still contends that the MMR vaccine contributes to autism (Ziv, 2015).

Many researchers tried to duplicate this study and could not replicate Wakefield's results. In fact, they found no link between the vaccines, bowel disease, and autism. In the United Kingdom, the MMR vaccine was not introduced until 1988. If Wakefield's conclusions were correct, one would then expect a jump in autism cases after 1988, but this was not observed, even when hundreds of children were studied (Taylor et al., 1999). In these additional studies, children who had not been vaccinated were included as a control group, and no difference in the rates of autism was observed.

In 2011, Brian Deer reviewed Wakefield's study and all available records from the National Health Service (NHS) in the United Kingdom for these 12 children. He found that at most, two children showed symptoms days after vaccinations. At least five children showed developmental delays before being vaccinated. Six out of the 12 children may have had autism symptoms. None of the 12 children tested had all three-regressive autism, colitis, and symptoms days after vaccination.

Symptom	Wakefield	Wakefield NHS Records (Deer)
Symptoms days after vaccination	8	2?
Non-specific colitis	12	3
Regressive autism	9	6?
Intestinal/autism/symptoms after vaccine	12	0

(Wakefield, et al., 1998; Deer, 2011)

Wakefield's statements led to a worldwide panic about the safety of vaccines, but after Deer's report, Wakefield's study was retracted and his medical license was revoked for falsifying data. Click on the following links to review materials to enhance your knowledge of the scientific method and to support your analysis of Wakefield's experiment:

Steps of the Scientific Method: A simplified explanation of how the scientific method works, the steps taken to investigate phenomenon with diagrams

Do Vaccines Cause Autism?: A review of research demonstrating that vaccines and their components are not the cause of autism

Fifteen years after a vaccine scare, a measles epidemic: An analysis of vaccination trends and an increase in measles cases seen the UK

Answer the following 4 questions:

What was wrong with Wakefield's study? Discuss at least 1 variable or approach that should have been controlled or assessed.

Consider the source of some of his data (parental memory, for example), the small sample size, and whether he considered other variables (genetics, diet, and so on) that could have resulted in symptoms in these children.

Discuss the importance of a control group when using the scientific method.

Did Wakefield deserve to be barred from medical practice?

What were the consequences of his inflated conclusions?

Case Study

Skolnikland is in Eastern Africa, with a population of 30 million people. The country has a plains region, a hill region, and a region with high mountains. It has a number of ecosystems. The plains are dry for much of the year, there is some rainforest, and the rest of the country includes both hills and mountains. There are two seasons of heavy rainfall.

The citizens come from several ethnic groups that tend to live in their own regions and speak different languages. The ethnic groups largely follow one of three different religions. The large cities are mixed ethnically. One ethnic group is economically and socially very dominant. The people from this group live in the capital and most of the large cities. The national language is the language of this dominant ethnic group.

According to World Bank criteria, Skolnikland is among the poorest countries in the world. The economy has been growing at about 4% per year on average over the last decade, but the economy had very slow economic growth in the decades prior to that. The richest 10% of the population controls 80% of the national income.

About 80% of the people live in rural areas and 20% in urban areas. The number of people living in urban areas has been growing recently at an increasing pace. Most people earn their livelihood in agriculture but there is an increasing garment manufacturing industry in the two largest cities. There are also a number of mining industries. In addition, other export industries are beginning to grow, mostly focused on the export of commodities to China.

The total fertility rate is about 4.5 but it has been declining slowly over the last two decades, from over 6. There is an almost equal number of men and women in the population. Infant mortality is about 90 per 1,000 live births. Maternal mortality is about 500 per 100,000 live births. Thirty-five percent of the children are underweight for age.

The adult literacy rate is about 40%. The educational enrollment rate, especially for girls at the primary and secondary levels, has been growing slowly, but steadily. Most recently, this rate has been growing at an increasing pace and about 75% of the girls now attend school regularly, although many of them are of very low quality.

Only about 50% of citizens have access to safe water. Only about 30% have access to sanitary disposal of human waste.

HIV prevalence is 7% of the adult population. The number of new HIV cases annually has begun to plateau. About half of the people eligible for treatment for HIV are on treatment. Malaria is rampant in the plains.

Investments in the road system have been growing at a solid pace in the last decade and the use of private automobiles has begun recently to increase more rapidly.

Skolnikland has a pluralistic health system that is made up of public and private institutions, publicly financed providers, licensed private providers, unlicensed medical practitioners, and traditional healers. There is no health insurance, except for some free services for the poor in the few publicly financed hospitals, which the better off people do not attend. The health system is not very effective or efficient and is generally of low quality. The HIV, TB, and malaria programs are not effective or efficient and they are just beginning to adopt paradigms for services that follow global best practices.

QUESTION 26

What is a DALY?

Refer Case Study from question 1 to answer this question.

A. An indicator that compares the burden of deaths across the population of different countries.

B. A composite health gap indicator that measures the amount of health and disability-free life that is lost because of disease, injury, and premature death.

C. A WHO indicator used to summarize the expected number of years to be lived in good health.

QUESTION 27

What is an example of a conditional cash transfer that you can use to improve child health?

Refer Case Study from question 1 to answer this question.

A. Provide tax breaks to families with children.

B. Give money to mothers whose children received a full course of vaccination.

C. Pay higher fees to vaccination programs with better outcomes.

QUESTION 28

What usually takes place during the demographic transition?

Refer Case Study from question 1 to answer this question.

A. Fertility falls before mortality falls

B. Mortality falls and then fertility falls

C. Mortality and fertility fall at the same time

QUESTION 29

Which force is likely to have the greatest direct impact on epidemiological change in the medium and long terms on today's middle-income countries?

Refer Case Study from question 1 to answer this question.

A. Population growth

B. Population aging

C. Urbanization

QUESTION 30

Which is the most accurate statement about the distribution of age at death in Niger (a very low income country) and Norway (a very high income country) today?

Refer Case Study from question 1 to answer this question.

A. About 5% of the deaths in Niger are among those under 15, while the overwhelming majority of deaths in Norway are among those over 65.

B. About 30% of the deaths in Niger are among those under 15, while the overwhelming majority of deaths in Norway are among those over 65.

C. The overwhelming majority of deaths in both countries occur among people aged 65 and over.