Randomization is a process used in clinical trials to allocate participants to the different treatment groups in a trial. Randomization helps to ensure that the groups are similar in terms of prognostic factors and that the treatments are distributed evenly across the groups. This helps to minimize bias in the trial and to ensure that any observed differences between the groups are due to the treatments being studied, rather than to other factors.
There are several methods of randomization that can be used in clinical trials:
Simple randomization: This is the most basic method of randomization, in which each participant has an equal chance of being allocated to any of the treatment groups. Simple randomization can be achieved using a random number generator or by using a table of random numbers.
Stratified randomization: In stratified randomization, the participants are divided into subgroups (strata) based on certain prognostic factors (e.g., age, gender, disease severity) and the randomization is performed within each stratum. Stratified randomization helps to ensure that the treatment groups are balanced in terms of important prognostic factors.
Block randomization: In block randomization, the participants are randomly allocated to treatment groups in blocks of a fixed size (e.g., blocks of four). This helps to ensure that the treatment groups are balanced in terms of the number of participants over time.