A new study is conducted to investigate the efficacy of intravenous immunoglobulin versus analgesics on pain alleviation in patients with idiopathic small fiber neuropathy. A total of 100 eligible patients who fulfilled the inclusion/exclusion criteria are assigned to one of two groups based on random selection by a computer. The method of assigning patients to treatment groups in this study is most likely to produce which of the following?

Question

A new study is conducted to investigate the efficacy of intravenous immunoglobulin versus analgesics on pain alleviation in patients with idiopathic small fiber neuropathy.  A total of 100 eligible patients who fulfilled the inclusion/exclusion criteria are assigned to one of two groups based on random selection by a computer.  The method of assigning patients to treatment groups in this study is most likely to produce which of the following?

Quizplus · Accepted Answer

Randomization refers to the process of randomly (ie, by chance) assigning subjects to experimental groups (eg, treatment vs control group). Randomization prevents selection bias and potentially produces comparable groups by balancing the frequency of confounding variables (eg, sex, age, severity of disease) between experimental groups. Making experimental groups as similar as possible (except for the treatment assigned) cancels the effect that these characteristics may have on the outcome of interest. For example, having groups that are dissimilar (ie, unbalanced) with respect to severity of disease may underestimate or overestimate the effect of a treatment, depending on which group has a greater proportion of severe cases. The best way to account for the effects of these variables is to randomly assign subjects to experimental groups. Afterward, the groups are analyzed to ensure that they are statistically similar in underlying variables, with the results often reported in a baseline characteristics table (eg, weight, sex, age). Therefore, randomization increases the likelihood that any difference observed between groups is due exclusively to the treatment and not to other characteristics. (Choices A and B) A blind study is a type of clinical trial in which either the participants or the researchers (ie, single blind) or both the participants and the researchers (ie, double blind) are unaware of treatment assignments. Although this study used randomization to assign patients to treatment groups, no information is provided regarding the awareness of participants or researchers to treatment assignments. By itself, randomization does not make a study blind. (Choice C) A study that analyzes all participants as initially allocated after randomization, regardless of what happens during the study period, is using an intention-to-treat (ITT) analysis. ITT is not a result of randomization; instead, it is used to preserve the effect of randomization. (Choice D) Depending on the randomization method (eg, simple, complete) used to allocate participants into experimental groups, a study may or may not result in groups that are similar in sample size. Regardless, the goal of randomization is not to create groups of similar size (which can be done trivially by alternating group assignment as patients enroll) but rather to make the underlying characteristics of experimental groups as similar as possible. Educational objective: Randomization refers to the process of using random methods to assign subjects to experimental groups. Its purpose is to make experimental groups as similar as possible (except for the treatment assignment) to ensure that any difference observed between the groups is due exclusively to the treatment and not to other underlying factors. __________ References: Randomized allocation to treatment groups and the importance of adjusting for covariates. (http://www.ncbi.nlm.nih.gov/pubmed/25032036)

A New Study Is Conducted to Investigate the Efficacy of Intravenous