Case Control Study


Observational Study

Observatory = Observational Study
Retro outfit = Retrospective study
Doesn't demo cause/effect

Case Control

Suitcase = Case
Zebra case and Zebra arm = Diseased

Survey and Interview

Looking for associations

Control Group

Controller = Control Group
Odds ratio = Gambling table
Zebra arm throwing dice = Higher Odds

Case Control Study

  • Its an observational study
  • Often times using surveys and interviews
  • Retrospective study ( goes back in time )
  • Does not demonstrate cause and effect
  • Compares those with disease with those without
  • Case study is an in-depth examination of a single research participant
  • Case studies enable researchers to obtain detailed knowledge about a person.  
  • They also provide an opportunity to conduct in-depth studies on rare and unusual cases
  • Results of a case control study can be used to find an "odds ratio” where the person with the causing factor having a higher odd of developing the disease
  • case-control study is a type of observational study in which two existing groups differing in outcome are identified and compared on the basis of some supposed causal attribute. Case-control studies are often used to identify factors that may contribute to a medical condition by comparing subjects who have that condition/disease (the "cases") with patients who do not have the condition/disease but are otherwise similar (the "controls")
  • Case-control studies are a relatively inexpensive and frequently used type of epidemiological study that can be carried out by small teams or individual researchers in single facilities in a way that more structured experimental studies often cannot be. They have pointed the way to a number of important discoveries and advances. The case-control study design is often used in the study of rare diseases or as a preliminary study where little is known about the association between the risk factor and disease of interest.[6]
  • Compared to prospective cohort studies they tend to be less costly and shorter in duration. In several situations they have greater statistical power than cohort studies, which must often wait for a 'sufficient' number of disease events to accrue.
  • Case-control studies are observational in nature and thus do not provide the same level of evidence as randomized controlled trials. The results may be confounded by other factors, to the extent of giving the opposite answer to better studies. A meta-analysis of what were considered 30 high-quality studies concluded that use of a product halved a risk, when in fact the risk was, if anything, increased. It may also be more difficult to establish the timeline of exposure to disease outcome in the setting of a case-control study than within a prospective cohort study design where the exposure is ascertained prior to following the subjects over time in order to ascertain their outcome status. The most important drawback in case-control studies relates to the difficulty of obtaining reliable information about an individual’s exposure status over time. Case-control studies are therefore placed low in the hierarchy of evidence.

Case Control Study Script

1. Zoom: Scientist with time machine and no cause/effect sign

Hot Spot: Observation study = observatory; retrospective study = retro outfit and turning back time; case control doesn’t demonstrate cause/effect = no cause/effect sign

Information Script: An observational study, a case control study is one in which two groups are compared on the basis of a speculative causal quality. Usually retrospective in nature, the study does not actually prove cause and effect. The observatory will help you to remember that we're looking at observation studies, and Wanda's retro outfit will provide a visual cue for retrospective studies. Case control doesn't demonstrate cause and effect, and the no cause/effect sign will aid in recalling that.

Story Script: Dr. Wanda Wayback loved the 1960s so much she can’t wait to return. She’s throwing a cause/effect understanding of time out the window and seeing it instead as a retrospective cycle. Using her Wayback Machine at the observatory, Dr. Wayback has donned her favorite retro bellbottoms and go-go boots for a wild ride back to see how medicine worked in the Age of Aquarius!

2. Zoom: Man with zebra briefcase and hand, and two other men with briefcases

Hot Spot: case = suitcase; diseased = zebra arm

Information Script: Instead, it compares two populations—one with a specific medical condition to one without. The subjects with the medical condition are referred to as the “cases,” while those without the condition are the “controls.” A case is shown here by the suitcase, and the zebra arm will help you to remember that it is diseased.

Story Script: And she’s arrived just in time! Turns out the Mad Men suit and tie crowd is in need of a little modern medicine—a top exec is experiencing a mysterious di-zebra! Zebra Fever, a skin condition, has Mr. Case in a panic, and Bill and Ted, wealthy brothers and CEOs of Control Group Ltd., are reconsidering that merger….

3. Zoom: Dr. Wayback interviewing the three men

Hot Spot: diseased & non-diseased = zebra and non-zebra rash

Information Script: Both are surveyed and interviewed on facts that might draw associations to a factor for that disease. In this case, the doctor is looking for feedback from both the zebra and non-zebra rash, or the diseased and non-diseased participants.

Story Script: Dr. Wayback decides to interview both Mr. Case and the Control Group brothers to try and determine what’s causing the Zebra Fever—stats, facts, where they’ve traveled over the past six months, anything that could get her to the bottom of this case. There are no easy answers, and she’s running out of funding.

4. Zoom: Dr. Wayback controlling the brothers and Mr. Case at the craps table

Hot Spot: control group = controller; odds ratio = gambling table; higher odds = zebra arm throwing dice

Information Script: Results of a case control study can help identify an odds ratio, shown here by the zebra arm throwing the dice, for a particular medical condition. This measurement quantifies the incidence of relative risk that an outcome will occur, given a causative factor. The controller in this picture represents the control group, while the odds ratio is seen in the gambling table.

Story Script: One interesting symptom of Mr. Case’s mysterious malady? The odds are always in his favor—a weekend in Atlantic City proves the man just can’t lose at the craps table when he throws with that diseased zebra arm of his! Suddenly, Dr. Wayback sees a path that will change the future of medicine—with remote control of the brothers, she’s got their minds and wallets both opened. Between Mr. Case’s luck and the brothers’ fortune, funding for her cause is ensured for at least another half century! Groovy!

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