The last step of the algorithm enforces an optional rule (employed
at Qwest) that only non-abandoning customers can contribute
positively to service level (that is, service level for any interval i can
be at most 1–Bi). For noninteger staffing levels (a consequence of
applying an availability factor to scheduled staff), values of Qi, Bi,
and Li can be obtained by interpolating between corresponding
results for bsic and dsie. When determining an interval staffing
requirement ri, we can calculate an initial service level based on
si ¼ ½lihi. We then increment or decrement si as needed until the
target service level is bracketed by the last two results, and
interpolate linearly between them to obtain ri. Since the expected
available staff on an interval need not be integer valued, similar
treatment of required staff is analytically appropriate. Additional
justification for non-integrality of ri follows from computational
reliance on expected values for the contributing parameters, which
will differ from the actual values observed in any particular
implementation.