Question

Which of the following would be the best method for randomly assigning subjects (n = 40) to treatment (n = 20) and control (n = 20) groups in an intervention study? Assign numbers to all subjects and:

a. ignore numbers; group the subjects by diagnosis or physician.
b. place the first 20 subjects in one group and the last in the other.
c. put even-numbered subjects in one group, odd numbered in the other.
d. put numbers 1 to 40 in a box and blindly draw from the box.

Answer 1

The best method for randomly assigning subjects to treatment and control groups is to put numbers 1 to 40 in a box and blindly draw them, known as simple random sampling. This ensures each subject an equal chance of being assigned to either group without introducing bias.

Step-by-step explanation:

The best method for randomly assigning subjects to treatment and control groups in an intervention study is to ensure that each subject has an equal chance of being in either group. Among the options provided, the method that accomplishes this is:

1. Put numbers 1 to 40 in a box and blindly draw from the box to assign subjects to the treatment and control groups. This method is known as simple random sampling and it ensures that there is no bias in the assignment process, giving each subject an equal opportunity to be in either group.

Other methods such as grouping by diagnosis, sequentially assigning subjects, or splitting by even or odd numbers may introduce bias or systematic differences between the groups, which could affect the outcome of the study.