Hey,
I have been doing an a priori sample size calculation but the figures I get are so small that I am no sure that they are correct. The primary outcome parameter is a PROM (max 100). I have the following values from a preliminary study for the intervention:
Mean±SD: 96±4
Sample siz: 39 patients
And I have the minimal clinically relevant change for the PROM, which would be 6.8
What would be the sample size I need, if I just want to hit the minimal clinically relevant change.
Thanks for you help!
Hi,
Here is calc. of sample size for one group and decrease in mean.It would be 6. done on g*power software.enclosed file
Bhogaraju Anand Thank you very much. I did calculate 5 per group. I am simply not sure whether this is the correct approach or not. Would you recommend another way of calculating it? The data I posted is the outcome following conservative treatment. There are published data on surgical treatment, but they use a different outcome score.
Please clarify the criteria you have taken as mean and standard deviation. Also which sampling method you want to adopt?
Understand the sampling method for better clarity.
Hi Sebastian. Which sampling method are you using? Is there any way to increase de sample size? In the way you describe de research it seems to be biased (as James Daniel Chindengwike
said).
We conducted a pilot study with 39 patients treated non-OP. Their mean±SD VAS FA Outcome socre was 96±4 points. For the VAS FA, the clinical minimal detectable change ist 6.8 points. Can these figures be used to calculate a sample size for a prospective RCT (1:1 randomization) comparing surgery to non-OP treatment? I hope this does clariy some of your questions
- Badges
- Science topic