Final answer:
The Dickinson & O'Connell (1990) study involved a review of medical records followed by interviews with a random sample of patients.
Step-by-step explanation:
The Dickinson & O'Connell (1990) study methodology comprised several key components according to the information provided. Epidemiologists from the public health office began by reviewing medical records and then moved on to conducting interviews with a randomly selected sample of patients to further understand the subject of their study. The goal of these interviews was likely to collect detailed, firsthand accounts to complement the data obtained from the medical records, thus providing a richer and more complex understanding of the health phenomena under investigation.