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Table 1 Rules used to determine correct classification and misclassification of TCA exposure status across all strata

From: A data visualisation method for assessing exposure misclassification in case-crossover studies: the example of tricyclic antidepressants and the risk of hip fracture in older people

Stratum Stratum Definition Rule
A Recent stoppers with CW1 becoming non-users with CW2 If greater than half of the latest prescriptions were closer to the RHS of CW1 than the LHS of CW1, then correct classification with CW1 and misclassification with CW2.
B Non-users with CW1 becoming recent stoppers with CW2 If greater than half of the people had a dispensing in the washout period, then misclassification with CW1 and correct classification with CW2. Those exposed in CW2 only were considered to be misclassified as recent stoppers due to the 150-day gap before hip fracture.
C Recent stoppers with CW1 remaining recent stoppers with CW2 If greater than half of the latest prescriptions were closer to the RHS of CW1 than the LHS of CW2, then correct classification in both CW1 and CW2.
D Intermittent users with CW1 becoming continuous users with CW2 If greater than half of the latest prescriptions were closer to the RHS of CW2 than the LHS of CW2, then misclassification with CW1 and correct classification with CW2.
E Continuous users with CW1 becoming intermittent users with CW2 If greater than half of prescriptions were closer to the LHS of CW1 than the RHS of CW1, then correct classification with CW1 and misclassification with CW2.
F Intermittent users with CW1 remaining intermittent users with CW2 If greater than half of the earliest prescriptions were located in the case window rather than the washout period, then correct classification in both CW1 and CW2.
  1. CW1 Control window 1, CW2 Control window 2, RHS Right-hand side, LHS Left-hand side