Statistics Terms Flashcards
Approaches to data analysis that provide a posterior probability distribution for some parameter (e.g. treatment effect), derived from the observed data and a prior probability distribution for the parameter. The posterior distribution is then used as the basis for statistical inference.
Bayesian Approach
The systematic tendency of any factors associated with the design, conduct, analysis and evaluation of the results of a clinical trial to make the estimate of a treatment effect deviate from its true value.
Bias
Bias introduced through deviations
Operational Bias
The checking and assessment of data during the period of time between trial completion (the last observation on the last subject) and the breaking of the blind, for the purpose of finalising the planned analysis.
Blind Review
The extent to which a variable (e.g. a rating scale) measures what it is supposed to measure.
Content Validity
A technique for retaining the blind when administering supplies in a clinical trial, when the two treatments cannot be made identical. Supplies are prepared for Treatment A (active and indistinguishable placebo) and for Treatment B (active and indistinguishable placebo). Subjects then take two sets of treatment; either A (active) and B (placebo), or A (placebo) and B (active).
Double Dummy
subject in a clinical trial who for any reason fails to continue in the trial until the last visit required of him/her by the study protocol.
Dropout
A trial with the primary objective of showing that the response to two or more treatments differs by an amount which is clinically unimportant. This is usually demonstrated by showing that the true treatment difference is likely to lie between a lower and an upper equivalence margin of clinically acceptable differences.
Equivalence trial
Statistical methods, such as significance tests and confidence intervals, which can be interpreted in terms of the frequency of certain outcomes occurring in hypothetical repeated realisations of the same experimental situation.
Frequentist Method
The set of subjects that is as close as possible to the ideal implied by the intention-to-treat principle. It is derived from the set of all randomised subjects by minimal and justified elimination of subjects
Full analysis set
The extent to which the findings of a clinical trial can be reliably extrapolated from the subjects who participated in the trial to a broader patient population and a broader range of clinical settings.
Generalisibility
A single variable, usually a scale of ordered categorical ratings, which integrates objective variables and the investigator’s overall impression about the state or change in state of a subject
Global assessment variable
An independent data-monitoring committee that may be established by the sponsor to assess at intervals the progress of a clinical trial, the safety data, and the critical efficacy endpoints, and to recommend to the sponsor whether to continue, modify, or stop a trial
Independent Data Monitoring Committee (IDMC) (Data and Safety Monitoring Board, Monitoring Committee, Data Monitoring Committee)
The principle that asserts that the effect of a treatment policy can be best assessed by evaluating on the basis of the intention to treat a subject (i.e. the planned treatment regimen) rather than the actual treatment given. It has the consequence that subjects allocated to a treatment group should be followed up, assessed and analysed as members of that group irrespective of their compliance to the planned course of treatment.
Intention-to-treat principle
The situation in which a treatment contrast (e.g. difference between investigational product and control) is dependent on another factor (e.g. centre).
Interaction
refers to the case where the magnitude of the contrast differs at the different levels of the factor
Quantitative interaction
the direction of the contrast differs for at least one level of the factor.
Qualitative interaction
The property of yielding equivalent results when used by different raters on different occasions.
inter-rater reliability
The property of yielding equivalent results when used by the same rater on different occasions.
intra-rater reliability
Any analysis intended to compare treatment arms with respect to efficacy or safety at any time prior to the formal completion of a trial.
Interim analysis
The formal evaluation of the quantitative evidence from two or more trials bearing on the same question. This most commonly involves the statistical combination of summary statistics from the various trials, but the term is sometimes also used to refer to the combination of the raw data.
meta analysis
clinical trial conducted according to a single protocol but at more than one site, and therefore, carried out by more than one investigator.
multicentre trial
A trial with the primary objective of showing that the response to the investigational product is not clinically inferior to a comparative agent (active or placebo control).
non-inferiority trial
lowest level of dictionary term to which the investigator description is coded
included term
is the level of grouping of included terms typically used in reporting frequency of occurrence.
preferred term
The set of data generated by the subset of subjects who complied with the protocol sufficiently to ensure that these data would be likely to exhibit the effects of treatment, according to the underlying scientific model. Compliance covers such considerations as exposure to treatment, availability of measurements and absence of major protocol violations.
Per Protocol Set (Valid Cases, Efficacy Sample, Evaluable Subjects Sample)
concerns the medical risk to the subject, usually assessed in a clinical trial by laboratory tests (including clinical chemistry and haematology), vital signs, clinical adverse events (diseases, signs and symptoms), and other special safety tests (e.g. ECGs, ophthalmology).
safety of a product
represents the degree to which overt adverse effects can be tolerated by the subject.
tolerability of a product
document that contains a more technical and detailed elaboration of the principal features of the analysis described in the protocol, and includes detailed procedures for executing the statistical analysis of the primary and secondary variables and other data.
statistical analysis plan
A trial with the primary objective of showing that the response to the investigational product is superior to a comparative agent (active or placebo control).
superiority trial
A variable that provides an indirect measurement of effect in situations where direct measurement of clinical effect is not feasible or practical
surrogate variable
An effect attributed to a treatment in a clinical trial.
treatment effect
An event that emerges during treatment having been absent pre-treatment, or worsens relative to the pre-treatment state.
treatment emergent
