Cohort Study

Data Collection

You have defined your hypotheses, exposure, participant eligibility criteria, and outcome... It's time to collect data.

5. What is the best source of information to assess Susser Syndrome (the outcome) among exposed and unexposed persons?

  1. Diagnosis of Susser Syndrome via hospital charts (based on neurological assessment and lab results)
  2. Complaints of neurological symptoms identified from employee health records
  3. Complaints of neurological symptoms based on information by the human resources department about medical leave of absence.
Answer (a) — correct: Neurological and lab assessments help ensure that cases are valid. We will not miss any cases because all persons with Susser Syndrome end up at the local hospital.
Answer (b) — incorrect: We might miss persons with Susser Syndrome who left work, or include persons whose symptoms are not fully consistent with the disorder.
Answer (c) — incorrect: Not all persons who contract Susser Syndrome will request a medical leave of absence. Therefore, we may miss many persons who had the disease or incorrectly identify persons as having the disease.

Your supervisor reads over your work and compliments you on a job well done. Before the study can begin and the data can be collected, however, your supervisor informs you of all the administrative work that must take place prior to the actual data collection.