Case Control Study Odds Ratio Interpretation
Another way to interpret the effect of the vaccine is to compare the odds of those who did not get the vaccine to those who did.To do so, you take the reciprocal of the odds ratio i.e. So children who did not receive childhood vaccines were 1.14 times as likely to have HPV compared to children who did receive childhood vaccines. You are investigating an outbreak of paralytic shellfish poisoning among patrons of an Alaskan restaurant.In a case-control study, we calculate the exposure odds ratio.The odds ratio approximates the incident rate ratio or risk ratio under certain conditions. The probability of an event occurring divided by the probability of it not occurring. And when the odds ratio is less than one, there is a negative association. Cross, the cross product formula only works if the table is set up correctly.Mathematically, this is the same as the cross product, which is equal to a times d divided by b times c.The odds ratio is the ratio of the odds of the health outcome or disease in the exposed Relative to the odds of the disease or health outcome in the none exposed or less exposed group.Data obtained from the cases and controls found that 218 cases and 45 controls consumed scallops.Now I'd like you to create a two by two table and calculate the odds ratio for this example and interpret your results, and then check back in a minute. 218 cases of paralytic shellfish poisoning and 45 controls who consumed scallops. There are other permutations, but here's a short one.
In this segment, you will learn how to define, calculate and interpret the odds ratio.And then we see there were 22 cases in 89 controls who did not consume scallops. Cases were 19.6 times as likely, compared to controls to have eaten the scallops.So to calculate the odds ration, you take the cross product, which is 218 times 89, divided by 45 times 22. As I said before, in a case control study, the odds ratio is the exposure odds ratio, which is the odds of being exposed in the cases equals a divided by c.Divided by the odds of being exposed in the controls or b divided by d.The first steps in learning to understand and appreciate evidence-based medicine are daunting to say the least, especially when confronted with the myriad of statistics in any paper.This short tutorial aims to introduce healthcare students to the interpretation of some of the most commonly used statistics for reporting the results of medical research.Or those in a traffic accident were 62% more likely to have been texting while driving.Then those who were not in a traffic accident in the past year.But the most precise interpretation is as follows the odds of a traffic accident among those who texted while driving was 1.62 times the odds of a traffic accident. Be careful, you cannot calculate a risk or rate directly from case control data.The denominators obtained in a case control study do not represent the total number of exposed and non-exposed person in the source population.