{"id":313,"date":"2022-06-16T20:56:06","date_gmt":"2022-06-16T20:56:06","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/alphamodule\/?post_type=chapter&p=313"},"modified":"2022-06-16T20:56:06","modified_gmt":"2022-06-16T20:56:06","slug":"observational-studies-apply-it-2","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/alphamodule\/chapter\/observational-studies-apply-it-2\/","title":{"raw":"Observational Studies: Apply It 2","rendered":"Observational Studies: Apply It 2"},"content":{"raw":"Let's explore a recent, important example of an observational study.\r\n\r\nIn March 2020, COVID-19 was declared a pandemic by the World Health Organization. In December 2020, vaccines using Messenger RNA technology were given emergency use authorization by the Food and Drug Administration in the United States. Over the next 13 weeks, 3,950 health care personnel, first responders, and other essential and frontline workers who had received the vaccine completed weekly COVID-19 testing to determine whether they had tested positive for COVID-19. In this study, researchers were following the effectiveness of the vaccines in a real-world setting.\r\n\r\nFor more information about this study, visit\u00a0https:\/\/www.cdc.gov\/mmwr\/volumes\/70\/wr\/mm7013e3.htm<\/a>.\r\n\r\nWork in groups or pairs to answer Questions 2 - 6.\r\n
\r\n

question 3<\/h3>\r\nIdentify at least one potentially confounding variable in this study.\r\n\r\n[reveal-answer q=\"615811\"]Hint[\/reveal-answer]\r\n[hidden-answer a=\"615811\"]What other factors could influence someone's positive COVID-19 diagnosis? How reliable are Covid-19 tests? What constitutes a confounding variable?[\/hidden-answer]\r\n\r\n<\/div>\r\n
\r\n

question 4<\/h3>\r\nWhat are some differences between an experimental study and an observational study?\r\n\r\n[reveal-answer q=\"764539\"]Hint[\/reveal-answer]\r\n[hidden-answer a=\"764539\"]Consider the key mechanisms of experimental design vs the qualities you learned about observational studies in the preview assignment.[\/hidden-answer]\r\n\r\n<\/div>\r\nYou may wish to make some notes for yourself if you haven't already about the key differences between experiments and observational studies.\r\n\r\nAs you answer Questions 5 and 6, recall the definition of a confounding variable:\u00a0Remember the definition of a confounding variable: a variable that was not accounted for in a study and may actually influence other variables in a study.\r\n
\r\n

question 5<\/h3>\r\nA PhD student collects data at a local elementary school. For each student, she records their age, grade, height, weight, shoe size, GPA, and score on a state-wide reading test for elementary school-aged children.\r\n\r\n \r\n\r\nPart A: Is this an experimental or observational study?\r\n\r\n[reveal-answer q=\"39249\"]Hint[\/reveal-answer]\r\n[hidden-answer a=\"39249\"]Consider the method being used. Is there random assignment and manipulation of a factor of interest? Or is data being recorded on observational units?[\/hidden-answer]\r\n\r\n \r\n\r\nPart B: The PhD student observes that students with larger shoe sizes tend to score higher on the state-wide reading test. She concludes that having bigger feet improves reading ability. Can you explain why her reasoning is likely to be incorrect? Can you think of another explanation for the higher test scores?\r\n\r\n[reveal-answer q=\"555123\"]Hint[\/reveal-answer]\r\n[hidden-answer a=\"555123\"]Can you think of another way to link higher reading scores with bigger feet?[\/hidden-answer]\r\n\r\n<\/div>\r\n
\r\n

question 6<\/h3>\r\nA study finds that people living in high-density urban areas develop fatal lung cancer at lower rates than people living in low-density rural areas.\r\n\r\n \r\n\r\nPart A: Is this an experimental or observational study?\r\n\r\n[reveal-answer q=\"57784\"]Hint[\/reveal-answer]\r\n[hidden-answer a=\"57784\"]Is there a factor in this study that can be manipulated?[\/hidden-answer]\r\n\r\n \r\n\r\nPart B: A student reads this study and determines that living near many people prevents cancer. Can you think of other things that might explain why low-density areas see higher rates of lung cancer?\r\n\r\n[reveal-answer q=\"830656\"]Hint[\/reveal-answer]\r\n[hidden-answer a=\"830656\"]Why else might residents of low-density rural areas suffer from fata cancer diagnoses?[\/hidden-answer]\r\n\r\n<\/div>\r\n
\r\n

Guidance<\/h3>\r\n[Wrap-up: You've seen that experimental studies have treatments, random assignment of participants, cause-and-effect relationships, and controls. Observation studies on the other hand do not have different treatments, they do not randomly assign participants to treatments, and they have a lack of control (or knowledge) of confounding variables. You may wish to keep a list of these differences handy until you develop a deep understanding of the difference between experiments and observational studies. ]<\/span>\r\n\r\n<\/div>\r\n ","rendered":"

Let’s explore a recent, important example of an observational study.<\/p>\n

In March 2020, COVID-19 was declared a pandemic by the World Health Organization. In December 2020, vaccines using Messenger RNA technology were given emergency use authorization by the Food and Drug Administration in the United States. Over the next 13 weeks, 3,950 health care personnel, first responders, and other essential and frontline workers who had received the vaccine completed weekly COVID-19 testing to determine whether they had tested positive for COVID-19. In this study, researchers were following the effectiveness of the vaccines in a real-world setting.<\/p>\n

For more information about this study, visit\u00a0https:\/\/www.cdc.gov\/mmwr\/volumes\/70\/wr\/mm7013e3.htm<\/a>.<\/p>\n

Work in groups or pairs to answer Questions 2 – 6.<\/p>\n

\n

question 3<\/h3>\n

Identify at least one potentially confounding variable in this study.<\/p>\n

Hint<\/span><\/p>\n
What other factors could influence someone’s positive COVID-19 diagnosis? How reliable are Covid-19 tests? What constitutes a confounding variable?<\/div>\n<\/div>\n<\/div>\n
\n

question 4<\/h3>\n

What are some differences between an experimental study and an observational study?<\/p>\n

Hint<\/span><\/p>\n
Consider the key mechanisms of experimental design vs the qualities you learned about observational studies in the preview assignment.<\/div>\n<\/div>\n<\/div>\n

You may wish to make some notes for yourself if you haven’t already about the key differences between experiments and observational studies.<\/p>\n

As you answer Questions 5 and 6, recall the definition of a confounding variable:\u00a0Remember the definition of a confounding variable: a variable that was not accounted for in a study and may actually influence other variables in a study.<\/p>\n

\n

question 5<\/h3>\n

A PhD student collects data at a local elementary school. For each student, she records their age, grade, height, weight, shoe size, GPA, and score on a state-wide reading test for elementary school-aged children.<\/p>\n

 <\/p>\n

Part A: Is this an experimental or observational study?<\/p>\n

Hint<\/span><\/p>\n
Consider the method being used. Is there random assignment and manipulation of a factor of interest? Or is data being recorded on observational units?<\/div>\n<\/div>\n

 <\/p>\n

Part B: The PhD student observes that students with larger shoe sizes tend to score higher on the state-wide reading test. She concludes that having bigger feet improves reading ability. Can you explain why her reasoning is likely to be incorrect? Can you think of another explanation for the higher test scores?<\/p>\n

Hint<\/span><\/p>\n
Can you think of another way to link higher reading scores with bigger feet?<\/div>\n<\/div>\n<\/div>\n
\n

question 6<\/h3>\n

A study finds that people living in high-density urban areas develop fatal lung cancer at lower rates than people living in low-density rural areas.<\/p>\n

 <\/p>\n

Part A: Is this an experimental or observational study?<\/p>\n

Hint<\/span><\/p>\n
Is there a factor in this study that can be manipulated?<\/div>\n<\/div>\n

 <\/p>\n

Part B: A student reads this study and determines that living near many people prevents cancer. Can you think of other things that might explain why low-density areas see higher rates of lung cancer?<\/p>\n

Hint<\/span><\/p>\n
Why else might residents of low-density rural areas suffer from fata cancer diagnoses?<\/div>\n<\/div>\n<\/div>\n
\n

Guidance<\/h3>\n

[Wrap-up: You’ve seen that experimental studies have treatments, random assignment of participants, cause-and-effect relationships, and controls. Observation studies on the other hand do not have different treatments, they do not randomly assign participants to treatments, and they have a lack of control (or knowledge) of confounding variables. You may wish to keep a list of these differences handy until you develop a deep understanding of the difference between experiments and observational studies. ]<\/span><\/p>\n<\/div>\n

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