The result is the weighted sum of the inputs was 25.7 Teller Hours
which was 85.7%, the efficiency rating of the amount used by B2 and
the weighted sum of the Supply $s was 171 which is 85.7% of the
amount used by B2 meeting constraint (b) above. The weighted sum
of the outputs, transactions processed, was 1000, which is equal to the
output of B2. When the 6 is below 1 or 100%, the above situation
results where there are groups of ERS units that produce as much or
more outputs and use less inputs offering a path to improve efficiency
of the inefficient units. When DBA tries to minimize 6 for the
service unit being evaluated and it cannot find /I weights that will
generate an efficiency level below 1 or 100%, this defines a relatively
efficient unit where there is no opportunity to improve efficiency
compared with the performance of other service units in the data set.
In DBA, model (2.1) is referred to as "multiplier model" where u^
and V. represent output and input multipliers (weights), respectively.
Model (2.2) is referred to as "envelopment model". We next illustrate
how to solve DBA models (2.1) and (2.2) via Microsoft® Bxcel
Solver and how to obtain the information on the Efficiency Reference
Set.