1. Why Are These Students Getting Sick?DZ
In Investigation 1-1: Why Are These Students Getting Sick? students will observe how a fictitious disease (“DZ”) is distributed and develop hypotheses about what might have caused that DZ distribution.
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Intro to Epidemiology - Investigation 1-1: Why Are These Students Getting Sick?
Investigation 1-1

2. Why Are These Students Getting Sick?DZ
☼ Teacher Alert: Do not tell students on what basis you decide which ones receive DZ signs. ☼
As students enter the classroom, hand out DZ signs to all those wearing jewelry (e.g., earrings, watches, necklaces).
Explain that the DZ signs represent a fictitious disease and that students with the signs have this fictitious disease.
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Intro to Epidemiology - Investigation 1-1: Why Are These Students Getting Sick?
Investigation 1-1

3. How? How is “DZ” spread out in the class? Is there a pattern?
What do “DZ” students have in common?
Ask each student with a DZ sign to stand. Tell all students to observe how DZ is distributed.
Ask students:
■ How is DZ spread out among your classmates?
■ Do you see a pattern?
■ What do students with the DZ signs have in common?
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How is “DZ” distributed?
Intro to Epidemiology - Investigation 1-1: Why Are These Students Getting Sick?
Investigation 1-1

4. They are wearing jewelry.
How?
They are wearing jewelry.
Ask students:
■ How is DZ distributed?
Probe until students conclude that all those with DZ are wearing jewelry.
☼ Teacher Alert: There is a difference between describing how a disease is distributed and explaining why that distribution occurred. Accurately observing how DZ is distributed is the first step. With the next slide, be sure that students are taking the next step by trying to explain why DZ was distributed like this. ☼
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How is “DZ” distributed?
Intro to Epidemiology - Investigation 1-1: Why Are These Students Getting Sick?
Investigation 1-1

5. __________ causes “DZ.”
Why?
__________ causes “DZ.”
Now that the students have described how DZ is distributed, ask them:
■ Why do you think DZ is distributed like this? In other words, what exposure - something with which these students came in contact - might explain why they have DZ?
■ Can you fill in the blank in the sentence “_______________ causes DZ?”
Encourage multiple responses. Write them on the board.
For example, the reason DZ developed in students wearing jewelry could be that gold or silver causes DZ, imitation metals in contact with skin cause DZ, jewelry that is too loose or too tight causes DZ.
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Why is “DZ” distributed like this?
Intro to Epidemiology - Investigation 1-1: Why Are These Students Getting Sick?
Investigation 1-1

6. They are wearing something red.
How?
They are wearing something red.
☼ Teacher Alert: Remind students that they are pretending. There is no disease called DZ. They are looking for clues to find an explanation. Insist that the task be done quietly, thoughtfully, and respectfully. Tell them that most of the students in the class will be given a DZ sign at least once during Investigation ☼
Collect the DZ signs and redistribute them to all students who are wearing something red.
Ask each student with a DZ sign to stand.
Ask all students:
■ How is DZ spread out among your classmates?
■ Do you see a pattern?
■ What do students with the DZ signs have in common?
■ How is DZ distributed?
Probe until the students conclude that all those with DZ are wearing something red.
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How is “DZ” distributed?
Intro to Epidemiology - Investigation 1-1: Why Are These Students Getting Sick?
Investigation 1-1

7. __________ causes “DZ.”
Why?
__________ causes “DZ.”
Now that they have described how DZ is distributed, ask students:
■ Why do you think DZ is distributed like this? In other words, what exposure - something with which these students came in contact - might explain why they have DZ?
■ Can you fill in the blank in the sentence “_______________ causes DZ”?
Encourage multiple responses. Write them on the board.
For example, the reason DZ developed in students wearing something red could be that the dye used to color clothing causes DZ.
Ask students:
■ Can you think of exposures - something with which people come in contact— that we now know cause people to get sick? (Cigarettes, the sun, asbestos, lead, and alcohol)
Point out that many such exposures were not originally thought to cause disease.
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Why is “DZ” distributed like this?
Intro to Epidemiology - Investigation 1-1: Why Are These Students Getting Sick?
Investigation 1-1

8. Why Are These Students Getting Sick?
Hypothesis
A statement, based on observation or reasoning, that can be tested and supported or refuted through investigation.
If you think you might know the answer to a question, you can state the answer as if it were a fact and call it a hypothesis.
Tell students that their explanation for why DZ is distributed like this is called a hypothesis.
A hypothesis is an educated guess.
Ask students:
■ What makes a guess an educated guess?
■ Why have your guesses been educated ones? (They were based on observations of how DZ was distributed. Hypotheses come from observations.)
When students think they can answer the question “Why is DZ distributed like this?” they can state their guess as if it were a fact and call it a hypothesis. For example, if students think DZ is concentrated in those people wearing something red because the red dye causes DZ, the hypothesis is “Red dye causes DZ.”
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Intro to Epidemiology - Investigation 1-1: Why Are These Students Getting Sick?
Investigation 1-1

9. Hypothesis
Ask students to explain how describing the distribution of a DZ and formulating a hypothesis are similar to:
■ What a police officer does. (Why are cars stolen in this neighborhood? Hypothesis: “Cars are stolen in this neighborhood because there is not adequate lighting.”)
■ What a plumber does. (Why doesn’t the sink drain? Hypothesis: “The sink doesn’t drain because it is clogged.”)
■ What a weatherperson does. (Why won’t it stop raining? Hypothesis: “A warm air front is stalled over the city.”)
■ What a firefighter does. (Why is this building on fire? Hypothesis: “Someone dropped a match.”)
■ What a telephone repair person does. (Why can’t people make phone calls from this block? Hypothesis: “The telephone wire is disconnected from the main telephone line.”)
■ What an auto mechanic does. (Why doesn't the car start? Hypothesis: “The car needs a new battery.”)
■ What a business person does. (Why aren’t we selling as many video games as we did before? Hypothesis: “Our competition is selling them for less money.”)
■ What a doctor does. (Why did this patient get sick? Hypothesis: “The patient ate too much sugar.”)
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Intro to Epidemiology - Investigation 1-1: Why Are These Students Getting Sick?
Investigation 1-1

10. Why Are These Students Getting Sick?
Pathologist
Doctor
Pathologists, physicians, and epidemiologists all try to answer the question “Why are these people getting sick?”
Tell students that
■ A pathologist tries to answer the question “Why did this person get sick?” by studying microscopic tissue samples and organisms.
■ A doctor tries to answer the question by studying the signs, symptoms, and medical history of an individual patient.
■ An epidemiologist tries to answer the question by studying how a disease is distributed in groups or populations of people.
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Epidemiologist
Intro to Epidemiology - Investigation 1-1: Why Are These Students Getting Sick?
Investigation 1-1

11. Epi Speak Epi Speak Population All the people in a particular group.
Tell students that Epi Speak is epidemiologists’ lingo. It consists of words, phrases, and concepts that epidemiologists use to talk about their investigations.
At the beginning of the investigations for each Enduring Understanding, students will be given an Epi Speak list.
It is more important for students to understand and use the “talk” than to memorize it. They will develop an understanding of the Epi Speak by conducting and speaking about the investigations. Give students the Epi Speak notes for all of the investigations for Module 1.
Ask students to find “Population” in the Epi Speak list.
Review its definition.
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Intro to Epidemiology - Investigation 1-1: Why Are These Students Getting Sick?
Investigation 1-1

12. Disease Detectives Detectives Investigate crimes
Look for clues at a crime scene
Judge quality of evidence
Form hypotheses
Identify suspects
Present evidence in court
Help control crime
Epidemiologists
Investigate diseases
Look for clues in the community
Judge quality of evidence
Form hypotheses
Identify suspected causes
Present evidence in scientific journals and at scientific meetings
Help control disease
Tell students that epidemiologists look at how real diseases are distributed among groups of people and formulate hypotheses to try to explain why people are sick. Epidemiologists are called disease detectives.
Detectives investigate crimes, look for clues at a crime scene, judge the quality of evidence, form hypotheses, identify suspects, present evidence in court, and help control crime.
Epidemiologists, disease detectives, investigate diseases, look for clues in the community, judge the quality of evidence, form hypotheses, identify suspected causes, present evidence in scientific journals and at scientific meetings, and help control disease.
As students complete the investigations in the Intro to Epidemiology curriculum, they will be developing the understandings and skills of an epidemiologist and will be disease detectives in training.
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Intro to Epidemiology - Investigation 1-1: Why Are These Students Getting Sick?
Investigation 1-1

13. Epi Speak Epi Speak Epidemiology
The study of how and why diseases or other health-related conditions are distributed in a population the way they are; in other words, why some people get sick and others do not.
Ask students to find “Epidemiology” in the Epi Speak list.
Review its definition.
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Intro to Epidemiology - Investigation 1-1: Why Are These Students Getting Sick?
Investigation 1-1

14. Epi Speak Epi Speak Disease Distribution
The pattern of how a sickness is spread out among a group of people.
Ask students to find “Disease distribution” in the Epi Speak list.
Review its definition.
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Intro to Epidemiology - Investigation 1-1: Why Are These Students Getting Sick?
Investigation 1-1

15. Epi Speak Epi Speak Hypothesis
An idea, based on observation or reasoning, that can be tested or supported or refuted through investigation.
Ask students to find “Hypothesis” in the Epi Speak list.
Review its definitions.
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Intro to Epidemiology - Investigation 1-1: Why Are These Students Getting Sick?
Investigation 1-1

16. Questions to Consider Epi Log Worksheet
Is my description of the distribution of “DZ” accurate?
Do I appreciate the uncertainty of my hypothesis?
Are my hypotheses logical? Do they make sense?
Am I willing to consider hypotheses that are different from my own?
Ask students to use the following questions to judge the quality of their work:
■ Is my description of the distribution of DZ accurate?
■ Are my hypotheses logical? Do they make sense?
■ Do I appreciate the uncertainty of my hypothesis? Although a hypothesis is an educated guess, it is still a guess.
■ Am I willing to consider hypotheses that are different from my own?
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Intro to Epidemiology - Investigation 1-1: Why Are These Students Getting Sick?
Investigation 1-1

17. Epi Speak Epi Speak Epidemiologist
An investigator who studies the occurrence of disease in populations of people for the purpose of preventing or controlling health problems.
Explain to students that just as a detective investigates a crime scene and looks for clues to identify possible suspects, they, as “Intro to Epidemiology,” have investigated a DZ scene, looked for clues, and identified possible hypotheses.
Remind students that people who investigate DZ scenes, look for clues, and identify possible hypotheses are called epidemiologists—disease detectives.
Ask students to find “Epidemiologist / Disease detective” in the Epi Speak list.
Review its definition.
Emphasize that in today’s class, when they tried to answer the question “Why are these people getting sick?” they were practicing the same skills that epidemiologists use to investigate acquired immunodeficiency syndrome (AIDS), anthrax, West Nile Fever, severe acute respiratory syndrome (SARS), violent behavior, and diabetes.
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Intro to Epidemiology - Investigation 1-1: Why Are These Students Getting Sick?
Investigation 1-1

18. Epi Speak Epi Speak Descriptive Epidemiology
Study of the distribution of a disease or other health-related condition.
Basis for formulating hypotheses.
Tell students that when they looked at how DZ was distributed among their classmates and formulated hypotheses, they were practicing descriptive epidemiology.
Ask students to find “Descriptive Epidemiology” in their Epi Speak list and review the definitions.
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Intro to Epidemiology - Investigation 1-1: Why Are These Students Getting Sick?
Investigation 1-1

19. Why Are These Students Getting Sick?
Investigation has ended.
Tell students that this concludes Investigation 1-1 and they can now put their Epi Logs away.
Intro to Epidemiology - Investigation 1-1: Why Are These Students Getting Sick?
Investigation 1-1