Glossary Terms Flashcards
hypothesis stating that there is no difference between the study groups
null hypothesis
probability that a difference between study groups would have occurred if the null hypothesis was true
P value
range in which we can be approximately 95% certain that the population value lies
95% confidence interval
When the null hypothesis is incorrectly rejected; a difference between groups is statistically significant although a clinically important difference exists
alpha error; false positive
Type I Error
When the null hypothesis is incorrectly accepted; a difference between groups is not statistically significant although a clinically important difference exists
Type II Error
number of new cases of a condition that develop in a population during a defined time period (cases/year)
incidence
total number of people in a population with a condition during a given point in time (cases at birth)
prevalence
statistic used to test whether the rate of an outcome is significant;y different between two or more exposure groups.
This test provides a probability that the outcome and exposure are independent
Chi-Square test
statistic used to test whether there is a linear trend for an outcome to increase or decrease over the range of an ordered categorial exposure variable
Chi-Square test for trend
the probability of an event or outcome occuring - such as infection, death, cure
risk
ratio of the probability of the outcome occurring in the exposed group, divided by the probability of the outcome occurring in the non-exposed group
relative risk
the probability of an event (p) occurring divided by the probability of that event not occurring (1-p)
odds
radio of the odds of the outcome occuring in one group divided by the odds of the outcome occurring in another group
odds ratio
initial trial of a new treatment to assess SAFETY and feasibility in a small group of volunteers who do not have the disease or patients with symptoms
Phase I Trial
clinical trial to measure EFFICACY - the effect of treatment under ideal conditions in patients with the disease
Phase II Trial
large randomized control trial or multi-center study to measure EFFECTIVENESS in the community - the effect of treatment in GENERAL CLINICAL PRACTICE
Phase III Trial
POST MARKETING survery to measure rare adverse events
Phase IV Surveillance
All participants are analyzed in the group to which they were allocated, regardless or subsequent events such as non-complicance or withdrawal from the study. This provides a conservative estimate of treatment effect that is not influenced by cofounders
Intention-to-Treat analysis
only participants with final study outcomes are included in the data analysis but participants are maintained in the group to which they were allocated - results may be influenced by bias and cofounders
Available-case analysis
participants are re-grouped according to the treatment they actually received, irrespective to te treatment to which they were allocated - by using this method there is no control of cofounders
treatment-received-analysis
number of people who need to receive a new treatment to prevent one adverse event from occurring
number-needed-to-treat (NNT)
frequency of the outcome in the control (current best practice treatment or placebo) group
control event rate (CER)
frequency of the outcome in the experimental (new treatment) group
experimental event rate (EER)