which keeps the numbers of subjects in each group similar at all times.
groups may be generated that are rarely comparable in terms of certain covariates.
ddresses the need to control and balance the influence of covariates.
balance among groups in terms of subjects’ baseline characteristics
le. Stratified randomization is achieved by generating a separate block for each combination of covari
This method is used to ensure a balance in sample size across groups over time. Blocks are small and balanced with predetermined group assignments, which keeps the numbers of subjects in each group similar at all times.
Use of online software to generate randomization code using block randomization procedure will be presented.
Statistical techniques such as analysis of covariance (ANCOVA), multivariate ANCOVA, or both, are often used to adjust for covariate imbalance in the analysis stage of the clinical research.
simple randomization, block randomization, stratified randomization, and covariate adaptive randomization
Blocks are best used in smaller increments as researchers can more easily control balance.
The stratified randomization method addresses the need to control and balance the influence of covariates.
This method can be used to achieve balance among groups in terms of subjects’ baseline characteristics (covariates).
Specific covariates must be identified by the researcher who understands the potential influence each covariate has on the dependent variable.
Although stratified randomization is a relatively simple and useful technique, especially for smaller clinical trials, it becomes complicated to implement if many covariates must be controlled.
Stratified randomization has another limitation; it works only when all subjects have been identified before group assignment. However, this method is rarely applicable because clinical research subjects are often enrolled one at a time on a continuous basis. When baseline characteristics of all subjects are not available before assignment, using stratified randomization is difficult.
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