All house cleaning data have been obtained from Denver Concierge, a large house cleaning company in Denver. The dataset consists of 179 observations, collected during a three month period, from July to September 2006. The unit of observations is “per cleaning assignment”. The details of each variable are discussed below.

At the time of the study, Denver Concierge employed 60 professional house cleaners on a full-time basis. The company conducts a central dispatch, applies a hybrid compensation scheme which takes into account employee time extending from departure time to return time, and uses its own vehicles for transportation. The cleaning times are gathered based on three separate parallel methods, the results of which are reconciled daily: 1) Team Leaders record arrival and departure time for each assignment on daily summary sheets; 2) Team Leaders phone the office to report arrival and departure time during each assignment; and 3) GPS vehicle tracking devices provide a time record of all vehicle stops.

In terms of scope of assignment, Denver Concierge targets the highest end customers in its market by offering exceptionally thorough cleaning. A range of home sizes were applied in the study.

Denver Concierge does not use a fixed team size. The Company deploys any mix of 2, 3, and 4 member teams daily, as a means of optimizing the schedule, as well as taking into account client-imposed constraints and continuity for important assignments.

Square Footage: an objective measurement in square feet of that portion of the residence which is to be included in the cleaning assignment. It can include only that square footage qualifying for measure by residential real estate appraisers, and thereby excludes below grade and unfinished areas. In many counties, this value is freely available on the county assessor’s office website. Also, some sites which access MLS comparable records disclose this statistic.

Basement Square Footage: the objective measurement in square feet of a Household’s entire basement, without regard to how much of the basement is in included in any given scope. This attribute is collected separately in order to provide a basis for a distinct incremental price for any change in scope. For example: Customer: “I know you don’t normally clean the basement, but can you please clean it during your next visit?” General Manager: “Sure, that will take us an extra man-hour and your extra charge will be 100 shekels.”

Basement Percent: for any given scope, the percent of basement to be cleaned (based on a scale of zero percent (0%), meaning “Don’t clean the basement”; to one hundred percent (100%), meaning “Clean the entire basement.” If a household has no basement, then the Basement Percent would be zero (0).

Number of Toilets: the objective count of the total number of rooms in a house which contain a toilet, avoiding the ambiguity associated with “half baths,” “powder rooms,” and “3/4 baths.” All toilets are included in the count without consideration for whether they are in normal use, since most house cleaning companies conservatively presume that every toilet has been used since the previous visit. Even for homes with low traffic, mineral deposits develop in unused toilets if it is not cleaned regularly. If the basement is excluded, then any toilets in the basement may be excluded from this count

Number of Showers in Use: the objective count of the number of showers and bathtubs normally in use by at least one person in the house since the previous house cleaning visit. A shower not in use does not materially impact clean time, and is not included in the shower count.