Now that you have your hypothesis and have learned the basic principles of the randomized trial study design, it's time to collect the data. First, you need to devise eligibility criteria, and also make sure you have developed an appropriate measure for the outcome of interest.

You decide on the following eligibility requirements for your study:

• Individuals must have been diagnosed with Stage I or II Susser Syndrome at Epiville General Hospital, but have no evidence of Stage III Susser Syndrome at the time of the study initiation.
• Individuals with medical conditions contraindicating treatment with KimFaderol are excluded
• Individuals with other severe illnesses giving them a low probability of surviving for at least 12 months are excluded

Of the 194 cases of Susser Syndrome diagnosed at the Epiville General Hospital, 120 meet the eligibility criteria. Luckily for you, all give informed consent and agree to participate in the study! You randomly assign 60 of these individuals to receive KimFaderol and 60 individuals to receive an inactive placebo.

To assess the outcome of interest, you assign a clinician to examine each study participant 12 months after the beginning of the study for evidence of severely impaired proprioception. The appearance of this impairment is very pronounced, and individuals are classified as having developed impaired proprioception if they can not move their hands or feet with their eyes closed. Individuals failing the proprioception assessment are classified as "Stage III " Susser Syndrome, while individuals not showing impaired proprioception are classified as "Stage I or II" Susser Syndrome.