Fig. 2.

Study design and data linkages. The figure represents the design of a record linkage study conducted at the sibling level. It focuses on deaths and person-years potentially included both in the reference and test data set (i.e., “reference sibships”) and establishes linkages at the individual level. In that example, we compare a list of the maternal siblings of a respondent obtained from SSH with a hypothetical reference data set. Paul, Peter, and James are “matches” (represented by the unidirectional arrows), Mary is a potential “addition,” and John and Julie are potential “omissions.” The age of Paul is misreported during SSH (35 vs. 32, “age error”), whereas the age of Peter is correctly reported. James’ age at death is misreported during SSH (27 vs. 24, “age error”) as is his date of death (2001 vs. 2004, “date error”). This latter date error leads James’ death to be misclassified as having occurred outside the eight-year reference period based on SSH data (when in fact it occurred in 2004, within the reference period).