Question

In a randomized control trial, if the participant and the physician/researcher don’t know to which group the participant is assigned, but the data analyst does, we say the study is...

a) not blinded

b) blind

c) double blind

d) triple blind

Answer 1

The answer is option (c) ie., double blind .

EXPLANATION

Blinding is the process of hiding the nature of the treatment that participants in a randomized controlled trial receive .

Blinding is a paramount feature of clinical trials that is framed to eliminate conscious or unconscious bias

The pieces of information regarding the treatment may be hidden from :

· the patients under treatment

· doctors

· researchers

· even the data analysts,who decipher the results.

Information may be hidden from one or more parties mentioned above .Each party ,mentioned above can act as a source of bias.

Blinding is a paramount feature of randomized controlled trial , that is framed to eliminate conscious or unconscious bias .

TYPES OF BLINDING:

1.In unblended/open label trials , all the parties are well informed about the treatment details ,that a patient receives.Here,no piece of information is hidden. Blinding is sometimes considered as inappropriate ,especially when a patient is being subjected to physiotherapy.In open label trials ,blinding technique is not used at all.

In the question ,the treatment details are masked from participants and physician.So, that is not open label study.There’s definitely a blinding technique applied.

Therefore,not option (a)

2.In single blind /single masked study,treatment details that participants receive is hidden only from the patients /participants.The doctors,researchers and data analysts/data interpreters are well aware of every minute details .

In the question ,the treatment details are masked from both participants and physician.So, that is not single blind study.

3.In double bind/double masked study,information regarding the treatment received by participants is hidden from the patients /participants and doctors /researchers.But,the data analysts/data interpreters know the treatment details to the fullest .

In the question ,the treatment details are masked from participants and physician ,but not from data analysts.So that comes under the category of ‘double blind study’.

4.In triple blind/triple masked study, information regarding the treatment participants receive is hidden from the patients /participants and doctors /researchers and data analysts/data interpreters.

In the question ,the treatment details are masked from participants and physician, but not from data analysts. So, that is not triple blind study.

Therefore,not option (d).

Option (b) is given as blind.Yes,blinding technique is used .But the type is not specified. Therefore,not option (b).

The answer is option (c) ie., double blind .