Randomization means, allocation by chance, not by choice. It's the phenomenon or process, used to reduced the biasness of the study. It has the ability to reduced the conflict of interest. Why I'm saying that because usually health care professional (doctors) have dual role, i.e, role of physician and role of clinician, in usually a large clinical trial. Randomization also permits the use of probability theory to express the likelihood of chance as a source for the difference between outcomes. The quality of the study will increase if carried out by the neutral person or outsider. Participants will usually be evenly placed in different study groups. Participants don't know to which group they've been assigned. One group receives the experimental intervention; the other receives standard or no treatment. This process is called randomization.
Randomization is everywhere in the world. True false test solution is the best example of randomization if somebody has not prepared the exam. Toss before the game of cricket is another example. Randomization can be done by tossing a coin, lottery, making slips, table of random numbers and computer software. Computer software is mostly used in large clinical trials.
Further, enrolment of subjects in a study should not be predictable, it should be un-predictable. For instance, physicians were told to divide the eligible children into a in to a group of immunized and control group, to see the effect of BCG, in a study. The mortality rate was came five times higher in controls than in vaccinated children, because children were selected consciously, from more health conscious families that have a lower risk of mortality from tuberculosis. This happened because assignment of next subject was predictable.
Let's assume that we've to choose only five presentations from fifty presentations, because of time constraint, which have been made by medical students. All students want to give presentations because the panel has come from all over Pakistan to decide grant for the research. Now because of ethical consideration, each and every student should have the equal chance to give presentation. Discrimination should be avoided. Now randomization is necessary. So, teacher has decided to make fifty paper slips (of equal size, same colour and same folding style) with roll numbers written on each student and then put them into a basket. The each member of the panel has to pick one slip from the basket with closed eyes. By doing this panel has given chance to five students for presentation and eliminated the bias.
So, it should be kept in mind that each and every body, who fulfils the criteria or protocol of the trial should be given equal chance for the sake of randomization.
References:
1. Gordis, L., (2009). Epidemiology, 4th ed., Sounders (Elsevier, Inc.), Philadelphia.
2. Randomization and computer software, [Online] available at http://mahmoodsaghaei.tripod.com/Softwares/randalloc.html, accessed on 20th July, 2013, at 11 pm.
Randomization is everywhere in the world. True false test solution is the best example of randomization if somebody has not prepared the exam. Toss before the game of cricket is another example. Randomization can be done by tossing a coin, lottery, making slips, table of random numbers and computer software. Computer software is mostly used in large clinical trials.
Further, enrolment of subjects in a study should not be predictable, it should be un-predictable. For instance, physicians were told to divide the eligible children into a in to a group of immunized and control group, to see the effect of BCG, in a study. The mortality rate was came five times higher in controls than in vaccinated children, because children were selected consciously, from more health conscious families that have a lower risk of mortality from tuberculosis. This happened because assignment of next subject was predictable.
Let's assume that we've to choose only five presentations from fifty presentations, because of time constraint, which have been made by medical students. All students want to give presentations because the panel has come from all over Pakistan to decide grant for the research. Now because of ethical consideration, each and every student should have the equal chance to give presentation. Discrimination should be avoided. Now randomization is necessary. So, teacher has decided to make fifty paper slips (of equal size, same colour and same folding style) with roll numbers written on each student and then put them into a basket. The each member of the panel has to pick one slip from the basket with closed eyes. By doing this panel has given chance to five students for presentation and eliminated the bias.
So, it should be kept in mind that each and every body, who fulfils the criteria or protocol of the trial should be given equal chance for the sake of randomization.
References:
1. Gordis, L., (2009). Epidemiology, 4th ed., Sounders (Elsevier, Inc.), Philadelphia.
2. Randomization and computer software, [Online] available at http://mahmoodsaghaei.tripod.com/Softwares/randalloc.html, accessed on 20th July, 2013, at 11 pm.
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