Control event rate
Encyclopedia
In epidemiology
and biostatistics
, the control event rate (CER) is a measure of how often a particular statistical event (such as response to a drug, adverse event
or death) occurs within the scientific control group
of an experiment .
This value is very useful in determining the therapeutic benefit or risk to patients in experimental groups, in comparison to patients in placebo
or traditionally treated control groups.
Three statistical terms rely on CER for their calculation: Absolute risk reduction
, Relative risk reduction
and Number needed to treat
.
, and the experimental group (25 people) is given drug "X".
Event "Z" in control group : 4 in 25 people
Control Event Rate : 4/25
Event "Z" in experimental group : 12 in 25 people
Experimental Event Rate
: 12/25
Another worked example is as follows:
Epidemiology
Epidemiology is the study of health-event, health-characteristic, or health-determinant patterns in a population. It is the cornerstone method of public health research, and helps inform policy decisions and evidence-based medicine by identifying risk factors for disease and targets for preventive...
and biostatistics
Biostatistics
Biostatistics is the application of statistics to a wide range of topics in biology...
, the control event rate (CER) is a measure of how often a particular statistical event (such as response to a drug, adverse event
Adverse event
An adverse event is any adverse change in health or side effect that occurs in a person who participates in a clinical trial while the patient is receiving the treatment or within a previously specified period of time after the treatment has been completed.AEs in patients participating in...
or death) occurs within the scientific control group
Scientific control
Scientific control allows for comparisons of concepts. It is a part of the scientific method. Scientific control is often used in discussion of natural experiments. For instance, during drug testing, scientists will try to control two groups to keep them as identical and normal as possible, then...
of an experiment .
This value is very useful in determining the therapeutic benefit or risk to patients in experimental groups, in comparison to patients in placebo
Placebo
A placebo is a simulated or otherwise medically ineffectual treatment for a disease or other medical condition intended to deceive the recipient...
or traditionally treated control groups.
Three statistical terms rely on CER for their calculation: Absolute risk reduction
Absolute risk reduction
In epidemiology, the absolute risk reduction or risk difference is the decrease in risk of a given activity or treatment in relation to a control activity or treatment. It is the inverse of the number needed to treat....
, Relative risk reduction
Relative risk reduction
In epidemiology, the relative risk reduction is a measure calculated by dividing the absolute risk reduction by the control event rate.The relative risk reduction can be more useful than the absolute risk reduction in determining an appropriate treatment plan, because it accounts not only for the...
and Number needed to treat
Number needed to treat
The number needed to treat is an epidemiological measure used in assessing the effectiveness of a health-care intervention, typically a treatment with medication. The NNT is the average number of patients who need to be treated to prevent one additional bad outcome...
.
Worked example
In a trial of hypothetical drug "X" where we are measuring event "Z", we have two groups. Our control group (25 people) is given a placeboPlacebo
A placebo is a simulated or otherwise medically ineffectual treatment for a disease or other medical condition intended to deceive the recipient...
, and the experimental group (25 people) is given drug "X".
Event "Z" in control group : 4 in 25 people
Control Event Rate : 4/25
Event "Z" in experimental group : 12 in 25 people
Experimental Event Rate
Experimental event rate
In epidemiology and biostatistics, the experimental event rate is a measure of how often a particular statistical event occurs within the experimental group of an experiment ....
: 12/25
Another worked example is as follows:
See also
- Experimental event rateExperimental event rateIn epidemiology and biostatistics, the experimental event rate is a measure of how often a particular statistical event occurs within the experimental group of an experiment ....
- Absolute risk reductionAbsolute risk reductionIn epidemiology, the absolute risk reduction or risk difference is the decrease in risk of a given activity or treatment in relation to a control activity or treatment. It is the inverse of the number needed to treat....
- Relative risk reductionRelative risk reductionIn epidemiology, the relative risk reduction is a measure calculated by dividing the absolute risk reduction by the control event rate.The relative risk reduction can be more useful than the absolute risk reduction in determining an appropriate treatment plan, because it accounts not only for the...
- Number needed to treatNumber needed to treatThe number needed to treat is an epidemiological measure used in assessing the effectiveness of a health-care intervention, typically a treatment with medication. The NNT is the average number of patients who need to be treated to prevent one additional bad outcome...