Question

Researchers were interested in determining a new drug for reducing high blood pressure. They obtained a sample of volunteers for the study and randomly divided them into two groups, C and T. A single medical practitioner, Dr. Daring, agreed to help the researchers in this study following a protocol of three steps: (i) The blood pressure of each subject was measured by Dr. Daring; (ii) the new drug was administered to subjects in group T and a placebo to subjects in group C. (iii) after a determined amount of time, Dr. Daring measured the blood pressure of all the subjects again and provided all this information to the researchers. Only the researchers and Dr. Daring knew if a subject received the new drug or a placebo, but neither the subjects nor the rest of doctors and nurses in the hospital where the study was conducted knew this information. After some data analysis, the researchers concluded that in fact the new drug lowered high blood pressure in patients. Select all the statements that are true (if a statement is partially not correct, you should not select that option):

Group of answer choices

This is an observational study

This is a double-blind experiment

This is a randomized controlled experiment

This observational study is controlling for high vs low blood pressure subjects

There was at least one obvious way to make this a better experiment

There are no reasons to doubt the conclusions obtained

Answer 1

1. Here, the objective is to test the efficacy of a new drug for lowering blood pressure. This requires the researcher himself to actually introduce an intervention (the new drug) and can control the conditions in which the study is conducted and not simply observe the patients being treated.

Hence, this is not an observational, but an experimental study.

2. In a double-blind experiment, neither the subject, nor the researcher must know the order of assignment of patients to the groups,i.e. a patient is assigned to which group.

But here, as mentioned, 'Only the researchers and Dr. Daring knew if a subject received the new drug or a placebo, but neither the subjects nor the rest of doctors and nurses in the hospital where the study was conducted knew this information', the researcher knew about the treatment group a patient being assigned to.

Hence, this is not a double blind study, but a single blind study.

3. A Randomized controlled experiment is a study in which people are randomly allocated to receive one of several clinical interventions. One of these interventions would be the control, which may be a standard practice, a placebo or no intervention.These studies measure and compare the outcomes - pre and post treatment.

Hence, this is a randomized controlled experiment.

Also, there was at least one obvious way to make this a better experiment.As mentioned in 2, here, since, it is a single blinded experiment, the outcomes are not free from bias from the part of the researcher. He / she may subjectively assign the treatment and control and hence this affects the credibility of the results of the experiment.

Hence, a double blined study is usually preferred to a Single blinded one.