about 50 percent in the Americas to

about 50 percent in the Americas to over 80 percent
in Europe, the Middle East, and Africa (EMEA)
and Asia.
The single-stage models were developed by P&G’s
internal OR group and implemented as end-user
spreadsheets for use by planners. We refer to Farasyn
et al. (2008) for a deeper discussion of our single-stage
inventory models, including a review of the design
choices, benefits, and weaknesses of spreadsheets as
the technology platform for this type of application.