What is a very big odds ratio?

An odds ratio of 4 or more is pretty strong and not likely to be able to be explained away by some unmeasured variables. • An odds ratio bigger than 2 and less than 4 is possibly important and should be looked at very carefully. •

Is an odds ratio of 2 high?

An OR of 2 means there is a 100% increase in the odds of an outcome with a given exposure. Or this could be stated that there is a doubling of the odds of the outcome. Note, this is not the same as saying a doubling of the risk.

What if odds ratio is greater than 1?

Important points about Odds ratio:

OR >1 indicates increased occurrence of an event. OR <1 indicates decreased occurrence of an event (protective exposure) Look at CI and P-value for statistical significance of value (Learn more about p values and confidence intervals here)

What does an odds ratio of 1.5 mean?

It means that the odds of a case having had exposure #1 are 1.5 times the odds of its having the baseline exposure. This is not the same as being 1.5 times as probable: odds are not the same as probability (odds of 2:1 against means a probability of 13).

Can an odds ratio be 100?

Probability values can only range from 0 to 1 (0% to 100%), whereas odds can take on any value.

Odds Ratios and Log(Odds Ratios), Clearly Explained!!!

How high can an odds ratio be?

As odds of an event are always positive, the odds ratio is always positive and ranges from zero to very large. The relative risk is a ratio of probabilities of the event occurring in all exposed individuals versus the event occurring in all non-exposed individuals.

Can an odds ratio be greater than 100?

A result greater than 100 represents greater odds of an outcome when exposed to a treatment. Conversely, an OR less than 1 indicates less odds of an outcome when exposed to the treatment.

What is ideal odds ratio?

An odds ratio greater than 1 indicates that the condition or event is more likely to occur in the first group. And an odds ratio less than 1 indicates that the condition or event is less likely to occur in the first group. The odds ratio must be nonnegative if it is defined.

What does an odd ratio of 0.4 mean?

For example, the odds ratio of 0.4 could mean, in numerical terms it means that for every 10 females without bowel cancer there are 20 who does, while in males, for every 10 individuals who do not have the tumor there are 50 who does”

What does an odds ratio of .75 mean?

"When you are interpreting an odds ratio (or any ratio for that matter), it is often helpful to look at how much it deviates from 1. So, for example, an odds ratio of 0.75 means that in one group the outcome is 25% less likely. An odds ratio of 1.33 means that in one group the outcome is 33% more likely."

Can odds ratio be 30?

Maybe it was a combination of low power and selection by significance that rendered so large an effect? With right-hand tapping, the odds ratio is 8/4/(7/4) = 1.1 (no framing effect). With left-hand tapping, it is 12/1/(3/9) = 36. So the ratio of odds ratios is about 30.

What is the rule of thumb for odds ratio?

But how big an effect is it? Epidemiologists use this very rough rule of thumb: An odds ratio of 4 or more is pretty strong and not likely to be able to be explained away by some unmeasured variables. An odds ratio bigger than 2 and less than 4 is possibly important and should be looked at very carefully.

Why is odds ratio exaggerated?

The odds ratio will always overstate the case when interpreted as a relative risk, and the degree of overstatement will increase as both the initial risk increases and the size of any treatment effect increases.

What does an odds ratio of 5.2 mean?

Consequently, an odds ratio of 5.2 with a confidence interval of 3.2 to 7.2 suggests that there is a 95% probability that the true odds ratio would be likely to lie in the range 3.2-7.2 assuming there is no bias or confounding.

What does an odds ratio of 0.8 mean?

Examples. RR of 0.8 means an RRR of 20% (meaning a 20% reduction in the relative risk of the specified outcome in the treatment group compared with the control group).

What is the odds ratio for dummies?

What is an odds ratio? An odds ratio (OR) is a measure of association between an exposure and an outcome. The OR represents the odds that an outcome will occur given a particular exposure, compared to the odds of the outcome occurring in the absence of that exposure.

What does an odds ratio of 0.1 mean?

From probability to odds

So a probability of 0.1, or 10% risk, means that there is a 1 in 10 chance of the event occurring.

How do you compare odds ratios?

The odds ratio is a way of comparing whether the odds of a certain outcome is the same for two different groups (9). (17 × 248) = (15656/4216) = 3.71. The result of an odds ratio is interpreted as follows: The patients who received standard care died 3.71 times more often than patients treated with the new drug.

What does an odds ratio of .98 mean?

The reported odd ratio of 0.98 at less than 1 indicates that for every additional parameter of the tested independent variable, they were . 98 times likely to report the likelihood of the test question.

What does an odds ratio of 0.70 mean?

In the study by Lin et al, the probability of the event was 59% and, using the calculation proposed by Davis et al,² we can estimate that the odds ratio of 0.70 is equivalent to a relative risk of 0.85—that is, the odds ratio is 18% smaller than the relative risk.

Is a low odds ratio good?

Yes. A low odds ratios indicates that the factor under examination is associated with a decrease, rather than an increase of risk relating to your outcome measure. Any significant departure from an odds ratio of 1 is of interest in understanding a factor's impact on outcomes.

Can odds ratio be infinite?

Odds = probability / (1 - probability) therefore odds can take on any value between 0 and infinity whereas probability may vary only between 0 and 1. Odds and log odds are therefore better suited than probability to some types of calculation.

What is the range of odds?

Probabilities always range between 0 and 1. The odds are defined as the probability that the event will occur divided by the probability that the event will not occur. If the probability of an event occurring is Y, then the probability of the event not occurring is 1-Y.

What is odds ratio mortality?

The odds are the ratio of the probability that an outcome occurs to the probability that the outcome does not occur. For example, sup- pose that the probability of mortality is 0.3 in a group of patients. This can be expressed as the odds of dying: 0.3/(1 − 0.3) = 0.43.

What is the odds ratio paradox?

The odds ratio paradox relates to three chained proportions com- pared between the same two groups, and involves the magnitude, but not the direction of the effect.