We are planning to do a fully remote clinical trial to test an online intervention for depression.

Recruitment flow:- Participants will see all the relevant information on a webpage. Participants may contact us to clarify any doubts regarding the study. Then they will complete two assessment forms to test the inclusion/exclusion criteria. Then, we will call the participants to validate their contact information (at this point we wouldn't know who will be assigned to which group). After that the participants will be asked to sign up to the intervention website. Then they will be randomized to the experimental or the control group. We will be using minimisation (using MinimPy) to randomize participants.

Blindedness:- The participants wouldn't know if they are assigned to the experimental or the control group (so it is definitely single-blind). Since there is no investigator who will be assessing the depression severity, there is no source of any human bias there (since double-blind trials are designed to eliminate investigator bias).

Intervention:- The intervention is fully stand-alone and online. However, there is a forum in the experimental group where everyone, participants and investigators, will be able to post questions and answer questions. But, that is an extra feature of the experimental group which we think will help participants with their problems. We will be in touch with the participants via telephone only once. All other correspondence, if any will be via email or through the website itself.

I was wondering if this can be called a double-blind study. I have seen other fully remote trials with a similar design but they haven't mentioned the term double-blind anywhere. Considering the fact that it is the gold standard, I am surprised that investigators did not mention it in their paper. That is the source of my confusion.

Any thoughts are welcome. Thanks in advance.