Study ConductGlossary Term
ICH E6(R3) Section 6.4
The process of assigning trial subjects to treatment or control groups using an element of chance to reduce bias in allocating interventions.
Randomization is the gold standard method for allocating participants to treatment groups in clinical trials, providing the strongest foundation for valid statistical inference about treatment effects. By using chance rather than investigator judgment or participant preference to determine assignments, randomization helps ensure that treatment groups are comparable with respect to both known and unknown factors that might affect outcomes. This balance enables investigators to attribute observed differences in outcomes to the treatments themselves rather than to baseline differences between groups.
Various randomization methods are employed depending on the trial design and practical considerations. Simple randomization uses a random sequence without constraints, analogous to flipping a coin for each assignment. Block randomization ensures that treatment groups remain balanced throughout enrollment by randomizing within blocks of predetermined size. Stratified randomization ensures balance within important subgroups by randomizing separately within strata defined by prognostic factors. Adaptive methods adjust randomization probabilities based on accumulating data to achieve specific objectives.
The integrity of the randomization process is essential for trial validity. The randomization schedule must be generated using validated methods that produce truly random sequences. The schedule must be concealed from those enrolling participants to prevent selection bias. Access to the schedule must be restricted to prevent inappropriate unblinding. Documentation must enable verification that the randomization was implemented as designed. Any departures from random assignment must be documented and considered in the analysis and interpretation of results.
Stratified randomization
"The study employed stratified randomization by disease severity and prior treatment history to ensure balanced distribution of these prognostic factors across the treatment and placebo groups."
Interactive response technology
"When the participant met all eligibility criteria, the coordinator called the interactive voice response system, which assigned the next available randomization number and dispensed the corresponding treatment kit."
A procedure in which one or more parties involved in the trial are kept unaware of the treatment assignment to reduce bias in the assessment of outcomes.
A professional employed by the sponsor or contract research organization who monitors clinical trials at investigational sites to ensure protocol compliance, data quality, and participant safety.
A specialized research professional who works at the investigational site under the supervision of the investigator to coordinate and manage the day-to-day operational aspects of clinical trials.
The act of overseeing the progress of a clinical trial and ensuring that it is conducted, recorded, and reported in accordance with the protocol, standard operating procedures, GCP, and applicable regulatory requirements.
Any change, divergence, or departure from the study design or procedures defined in the protocol that is not implemented through a formal protocol amendment.
ICH E6(R3) Section 6.4
The process of assigning trial subjects to treatment or control groups using an element of chance to reduce bias in allocating interventions.
Randomization is the gold standard method for allocating participants to treatment groups in clinical trials, providing the strongest foundation for valid statistical inference about treatment effects. By using chance rather than investigator judgment or participant preference to determine assignments, randomization helps ensure that treatment groups are comparable with respect to both known and unknown factors that might affect outcomes. This balance enables investigators to attribute observed differences in outcomes to the treatments themselves rather than to baseline differences between groups.
Various randomization methods are employed depending on the trial design and practical considerations. Simple randomization uses a random sequence without constraints, analogous to flipping a coin for each assignment. Block randomization ensures that treatment groups remain balanced throughout enrollment by randomizing within blocks of predetermined size. Stratified randomization ensures balance within important subgroups by randomizing separately within strata defined by prognostic factors. Adaptive methods adjust randomization probabilities based on accumulating data to achieve specific objectives.
The integrity of the randomization process is essential for trial validity. The randomization schedule must be generated using validated methods that produce truly random sequences. The schedule must be concealed from those enrolling participants to prevent selection bias. Access to the schedule must be restricted to prevent inappropriate unblinding. Documentation must enable verification that the randomization was implemented as designed. Any departures from random assignment must be documented and considered in the analysis and interpretation of results.
Stratified randomization
"The study employed stratified randomization by disease severity and prior treatment history to ensure balanced distribution of these prognostic factors across the treatment and placebo groups."
Interactive response technology
"When the participant met all eligibility criteria, the coordinator called the interactive voice response system, which assigned the next available randomization number and dispensed the corresponding treatment kit."
A procedure in which one or more parties involved in the trial are kept unaware of the treatment assignment to reduce bias in the assessment of outcomes.
A professional employed by the sponsor or contract research organization who monitors clinical trials at investigational sites to ensure protocol compliance, data quality, and participant safety.
A specialized research professional who works at the investigational site under the supervision of the investigator to coordinate and manage the day-to-day operational aspects of clinical trials.
The act of overseeing the progress of a clinical trial and ensuring that it is conducted, recorded, and reported in accordance with the protocol, standard operating procedures, GCP, and applicable regulatory requirements.
Any change, divergence, or departure from the study design or procedures defined in the protocol that is not implemented through a formal protocol amendment.