where nd is the number of times a destination was included in a purchased package and D is the total number of destinations.
Actual refers to the actual inclusion probability for the in-sample estimation data and predicted refers to the predicted inclusion
probability for the out-of-sample validation data. As seen in Table 7, WAPE ranges from 3.08% to 4.15% for Origin 1 insample
data and is consistently higher (3.19–5.04%) for Origin 1 out-of-sample data. Origin 2 packages did not have as many
purchased observations and in general, WAPE measures for Origin 2 are higher than those for Origin 1.