retrospective study

  1. D

    Sample Size Calculation/power calcuation for retrospective study

    Hi all, I recently completed a study looking at hospital records over a 5 year period (fixed population of participants based on study period). We looked at 'blood transfusion' as a binary measure (didn't receive a transfusion = 0, did receive a transfusion = 1) between three groups...
  2. victorxstc

    Is this study clinical trial or retrospective cohort?

    Hi We have a set of patients with dental implants in their mouths. We wanna evaluate whether implants in each patient's mouth are as sensitive as normal teeth (of the same patient) to tactile stimuli. So it can be a retrospective cohort, because we have split the sample based on the...