Fig. 1

Differences in how information is collected across case report forms. (a) Excerpts of “Specimen Collection” information from NWT (left) and BC (right). In this example, the different forms use abbreviations and encode specimen information at different levels of granularity. The NWT “Laboratory” section asks for “Specimen Collection Date: YYYY/MMM/DD”, along with checkbox options for “NP swab”, “Throat swab”, “Sputum”, and “Other (e.g. BAL), specify:”. The BC “Laboratory” subsection “Specimen Collected” asks for checkbox entry for “Upper respiratory (e.g., Nasopharyngeal or oropharyngeal swab)” and “Lower respiratory (e.g., sputum, tracheal aspirate, BAL, pleural fluid). (b) Excerpts of “Patient Setting” information from NWT (left) and BC (right). The NWT “Patient Setting” section requests checkbox entry for “Physician office/clinic”, “Home visit”, “ED (not admitted)”, “Facility (LTC, Corrections)”, and then lists checkboxes and YYYY/MMM/DD “Admission date” data for “Inpatient (ward)” and “Inpatient (ICU)”. The BC “Exposures” subsection for exposures that may have occurred 14 days prior to symptom onset request checkbox confirmation for settings of “Acute care facility”, “Long form care facility”, “Group home (community living)”, “Correctional facility”, “School or daycare”, “Workplace not otherwise specified”; along with the role/group relation via checkbox confirmation for “Staff”, “Resident / patient”, “Student”, and “Other, specify”. In this example, it can be observed that different questions are being asked using the same field, e.g., “LTC” and “Long term care facility”. Figure adapted from “Comparison and analysis of Canadian public health SARS-CoV-2 case report forms” [23]