Random assignment is the second necessary component of a randomized controlled trial, along with random selection. Once participants have been randomly selected from the population of interest, they should be randomly assigned to either receive the treatment (treatment group) or control treatment (control group). Experimental research designs require random assignment to truly yield a causal effect.
In experimental research designs, random assignment reduces any selection biases associated with sampling from populations and can account for both measured and unmeasured confounding variables. Another added benefit is that any differences in the treatment groups at baseline in regards to demographic, prognostic, or clinical variables can be assumed to occur by chance alone (also known as equipoise). Statistical adjustment can be made for any differences.
There are several different randomization methods used in experimental research designs: Simple randomization, unequal allocation randomization, stratified randomization, and blocked randomization.
In experimental research designs, random assignment reduces any selection biases associated with sampling from populations and can account for both measured and unmeasured confounding variables. Another added benefit is that any differences in the treatment groups at baseline in regards to demographic, prognostic, or clinical variables can be assumed to occur by chance alone (also known as equipoise). Statistical adjustment can be made for any differences.
There are several different randomization methods used in experimental research designs: Simple randomization, unequal allocation randomization, stratified randomization, and blocked randomization.
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