average service rate = average arrival rate, λ = μ there still will be LINE because of variability!!Not all even!! **when service rate < arrival rate, can only use TPT time!! TPT = WIP x CT = WIP/RATE(WIP and TPT are particular important in services) Multiple-stage process: the server with the least capacitywould govern the multi-stage process and forms the bottleneckand determines the wait time in the process!! (unbalanced demand with service capacity) If QUEUE/WIP is unavoidable, 1.Unoccupied time feels longer than occupied 2. Anxiety makes waits seem longer 3.Uncertain waits seem longer than known, finite waits 4.Unexplained waits
are longer than explained 5.Unfair waits are longer than equitable waits 6.The more valuable the service, the longer the customer will wait 7.Solo waits feel longer than group waits.
Managing service
: 1.
Sources of variability
: 1) variability in
INTERARRIVAL times (arrival rate)
: rate of new requests entering the system is not
UNIFORM
2) Variability in
Process Times
(servicing rate
) –
proficiency
varies among staff,
process approach
may vary among employees and
customer requirements
may vary. Combination of high rates, high variability and high utilization
rates
accumulate WIP
in the system and
increases TPT
. Get more accurate measurement of the arrival times:
OBSERVE on multiple days at different times of day;
REDUCE unnecessary variability in
arrival rates by scheduling!
2.
Managing server capacity utilization
: Match Demands/Arrivals with Capacity/Service Rate & Match People Serving With Those Being Served – 1)
Managing
Arrival Rates
: (
Demand management
)
Consider “Yield Management”: Incentivizing the smoothing and
shifting of demand
from peak periods using (i) call backs, (ii) pricing, (iii) promotions, (iv) by informing customers of wait times,
(v)
scheduling arrivals 2)
Managing Service Rates
: 1)
Pull problems off-line
for “SWAT Team” 2)
Schedule staff to peak loads
: forecast service demands, then match capacity to forecasted demand. 3)
Staff/resource flexibility
.
Pool and “flex” resources
by removing specialization; reduces work ‘lumpiness’; “pool” services across a region.
Assumes demands will not be high everywhere
simultaneously. 4)
Options to improve service performance: Simplification of processes
: reduce to the
minimum number of processes to deliver a quality product or service;
Parallelization of
operations
: Where possible perform
operations in parallel rather than serially;
Modularization of processes
: responsibilities well defined;
reduce overlaps in task coverage; eliminate gaps between task
coverage;
Standardization of processes
: performed
the same way for consistency of product and training of personnel;
Learning
: Build the skills of people working within it. Build task-specific skills and
build team familiarity with routine interactions
.
