What is a risk ratio of infinity?

The risk ratio takes on values between zero ("0") and infinity. One ("1") is the neutral value and means that there is no difference between the groups compared, close to zero or infinity means a large difference between the two groups on the variable concerned.

What is an odds ratio of infinity?

An odds ratio of infinity means that the lists are highly dependent (not independent), as one is contained in other.

What is a strong risk ratio?

A risk ratio greater than 1.0 indicates an increased risk for the group in the numerator, usually the exposed group. A risk ratio less than 1.0 indicates a decreased risk for the exposed group, indicating that perhaps exposure actually protects against disease occurrence.

What does a risk ratio of 1.25 mean?

“For example, if the Odds Ratio was, for example, 1.25, it would mean that the fact of being a woman is a risk factor for cancer because for every 10 women without a tumor there would be 50 with it, while for every 10 healthy men there would be only 40 diseased”.

What does a risk ratio of 0.5 mean?

For example, when the RR is 2.0 the chance of a bad outcome is twice as likely to occur with the treatment as without it, whereas an RR of 0.5 means that the chance of a bad outcome is twice as likely to occur without the intervention. When the RR is exactly 1, the risk is unchanged.

Medical Statistics - Part 7: OR and RR in Observational Studies

What does a risk ratio of 0.8 mean?

A relative risk that is less than 1.0 indicates that there is a lower risk among the people in Group A. • If the relative risk were 0.8, people in Group A would be 20% less likely than people in all other groups to die from a cause.

What does risk ratio of 0.7 mean?

If the Odds ratio is 0.7 then it indicates a protective effect - I.e a reduced odds of exposure in case vs control group. That reduced risk is 1-odds so will be 30 percent reduced risk fo exposure.

What does a risk ratio of 0.75 mean?

2c) A risk ratio of 0.75 means there is an inverse association, i.e. there is a decreased risk for the health outcome among the exposed group when compared with the unexposed group. The exposed group has 0.75 times the risk of having the health outcome when compared with the unexposed group.

What does a risk ratio of 0.2 mean?

An OR of 0.2 means there is an 80% decrease in the odds of an outcome with a given exposure.

What does a risk ratio of 0.15 mean?

Because it is an OR, we must say that for every 0.15 (or 15) persons who experience the event in the experimental group, 1 person (or 100 persons) will experience the event in the control group. That is, the odds are 15 to 100.

What are the 4 risk ratios?

The most common ratios used by investors to measure a company's level of risk are the interest coverage ratio, the degree of combined leverage, the debt-to-capital ratio, and the debt-to-equity ratio.

Is a 2 to 1 risk ratio good?

A positive reward:risk ratio such as 2:1 would dictate that your potential profit is larger than any potential loss, meaning that even if you suffer a losing trade, you only need one winning trade to make you a net profit.

What does risk ratio of 1.1 mean?

In general: If the risk ratio is 1 (or close to 1), it suggests no difference or little difference in risk (incidence in each group is the same). A risk ratio > 1 suggests an increased risk of that outcome in the exposed group. A risk ratio < 1 suggests a reduced risk in the exposed group.

Can odds be infinity?

Odds range from 0 and positive infinity.

What does infinity mean in the ratio test?

If r > 1 (including infinity), then the series is divergent. This means the infinite series sums up to infinity. If r = 1, then the series could either be divergent or convergent. Basically if r = 1, then the ratio test fails and would require a different test to determine the convergence or divergence of the series.

What happens if ratio test goes to infinity?

The Ratio Test

If the limit of |a[n+1]/a[n]| is less than 1, then the series (absolutely) converges. If the limit is larger than one, or infinite, then the series diverges.

What is a risk ratio of 3?

Risk ratios describe the multiplication of the risk that occurs with use of the experimental intervention. For example, a risk ratio of 3 for a treatment implies that events with treatment are three times more likely than events without treatment.

What does 50% higher risk mean?

An example when talking about risks of disease

Say the relative risk of the disease is increased by 50% in smokers. The 50% relates to the 4 - so the absolute increase in the risk is 50% of 4, which is 2. So, the absolute risk of smokers developing this disease is 6 in 100.

What does a relative risk of 1.67 mean?

These risks resulted in a relative risk of 1.67, meaning that the risk of the disease was 67% higher in the exposed group.

What does a relative risk of 2.8 mean?

Thus the relative risk of seizure when taking the specific medication is 2.8 (2.8 = 0.16 / 0.057). A person is 2.8 times more likely to have a seizure when taking the specific medication, but that is only a 0.103% increase in absolute risk (1 in 1000 increase in absolute risk).

Can risk difference be greater than 1?

An OR value of 1 means no difference in odds between groups, and larger value than 1 means increased odds in exposed group, interpreted as a positive association between having disease and having exposure.

What does a hazard ratio of 0.6 mean?

If an effective treatment reduces the hazard of death by 40% (i.e., results in an HR of 0.60), the hazard is only 0.6% per day, meaning the chances of surviving 1 day with this diagnosis are 99.4%, the chances of surviving 2 days are 0.994 × 0.994 = 0.988, and so forth.

Can a ratio be less than 1?

A ratio is always less than 1.

What is a statistically significant risk ratio?

As a measure of effect size, an RR value is generally considered clinically significant if it is less than 0.50 or more than 2.00; that is, if the risk is at least halved, or more than doubled.