Operations HW4
Allen Feng 2026 Mar 27th
a)At Ritz Carlton, quality is defined as courtesy and professionalism by providing guests the finest
personal service, and empathy by anticipating the guests’ needs. Any deviation from the customer’s
desired service level would be considered as a defect. To improve quality, Ritz Carlton aims to reduce
defects to zero.
According to the provided data, defects, or daily complaints, occur consistently at a rate between 0 to 1%
of total daily occupancies. This could be a quality problem if Ritz is trying to achieve 0 defects.
On the upside, the rate of complaints seems to have a decreasing trend overtime.
# of Daily Complaints/Total Daily Occupancy:
b) I expect incorrect reservation complaints to decline overtime. As technology improves, there will be
more advanced computer systems or software that could handle reservations more efficiently with less
error. This could reduce the number of incorrect reservation complaints which have been recurring
consistently at a rate between 0.2 to 0.5 % of total daily occupancies according to the provided data.
c) I would address room cleanness complaints first. Because room cleanness complaints account for
33.89% of total complaints in the provided data (while the next most significant complaint category only
accounts for 16.30%), room cleanness appears to be the most significant category. If part of those
complaints happens to have “assignable cause,” we could implement measures to reduce room cleanness
complaints which is a significant portion of total defects.
d) Basic Assumptions: p bar = 183/145070 = 0.13%, LCL>0.00%
According to the chart, the days which assignable cause of defects arose are: Jan 4th 1997, Jan 12th 1997,
Feb 7th 1997, April 20th 1997, July 20th 1997, Sep 25th 1997, Oct 1st 1997, Oct 19th 1997
e) Of the dates where assignable cause of defects arose, two-thirds of those dates are weekends (Saturday
and Sunday). Moreover, nearly 80% of those complaints are related to the housekeeping department’s
tasks. Based on this information, it is likely that the housekeeping department may be understaffed during
weekends, either due to a higher influx of guests staying at the Ritz (more people tend to spend time at
hotels during the weekend) or because some staff members are off for the weekend during that time.
Hypothesis: The assignable cause of the room cleanliness defects may be understaffing in the
housekeeping department on weekends, driven by increased guest volume or reduced staff availability.