# Experiment degsin

#### P123

##### New Member
A clinical trial is to be carried out using four different therapies A, B, C and D. The effects of the therapies on tumor size are to be compared. Four patients are to be tested, one on each of the four treatments, at each of six different hospitals. At the different hospitals, different protocols may be in place to administer the therapies, different staff will administer the treatments and the environment at the hospitals may be different.

What is the most appropriate experiment for this and why? I think a factorial design with blocking though I'm not 100% sure.

#### hlsmith

##### Less is more. Stay pure. Stay poor.
Are you expecting much of a difference on the outcomes between the treatment groups? How is the outcome formatted?

#### P123

##### New Member
Are you expecting much of a difference on the outcomes between the treatment groups? How is the outcome formatted?
Hi, this is a question asked to me so I presume the outcome is up for interpretation, looking at the question wording does it mean 24 patients altogether across the six hospitals? if so maybe we could compare the average increase/decrease in tumor size for each therapy?

#### fed2

##### Active Member
I think you are right, it says 6 hospitals x 4 treatments = 24 people. To me it seems like the question already tells you the most important aspect of the experiment, that the 4 treatments are all given at each of the 4 hospitals, which would be a complete block as you mentioned above. I guess it is given that you would randomize subjects to treatments.

As far ast the different staff and other issues mentioned, blinding is all you could do. I think you are out of degrees of freedom to do any adjustment for these factors? So im not really sure what they could be asking for.

#### P123

##### New Member
I think you are right, it says 6 hospitals x 4 treatments = 24 people. To me it seems like the question already tells you the most important aspect of the experiment, that the 4 treatments are all given at each of the 4 hospitals, which would be a complete block as you mentioned above. I guess it is given that you would randomize subjects to treatments.

As far ast the different staff and other issues mentioned, blinding is all you could do. I think you are out of degrees of freedom to do any adjustment for these factors? So im not really sure what they could be asking for.