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<br />Part III. <br /> <br />Statistical Analysis <br />This analysis utilizes water record data for households that received an irrigation <br />inspection in either 2004 or 2005. The CRC was responsible for processing all of the <br />water records obtained from the participating cities and was subsequently able to estimate <br />the amount of water used outdoors. To determine the effects that Slow the Flow <br />Colorado had on outdoor water usage, each household's water usage before the <br />inspection and after the inspection was analyzed. The statisticians concluded that <br />equivalent amounts of data would be needed for pre and post inspection analysis in order <br />to mal<e comparisons. In 2004 only one year of pre-inspection data was usable because <br />2002 (two years pre-inspection) was a major drought year in which significant mandatory <br />watering restrictions were in effect. For the 2005 study group, only one year of post- <br />inspection data was available. Therefore, for both study groups only one year of pre and <br />post-inspection data could be analyzed. Consideration of factors that might occur/change <br />annually and affect watering behaviors (such as drought or watering restrictions) deemed <br />that the 2004 participants be analyzed separately from the 2005 participants. <br />In 2004, four of the five participating cities provided residential irrigation inspections <br />through Slow the Flow Colorado. These cities were: Boulder, Erie, Lafayette, and <br />Longmont (auditors inspected parks in the City of Louisville). All cities participating in <br />2004 were analyzed as a whole as well as individually, with the exception of Longmont. <br />Longmont data was only analyzed individually and was not included in the analysis of <br />the 2004 group as a whole because the data characteristics varied significantly from the <br />rest of the cities and would have erroneously skewed the results for the group as a whole. <br /> <br />In 2005, there were seven cities that provided residential irrigation inspections through <br />Slow the Flow Colorado. These cities were: Boulder, Erie, Golden, Lafayette, <br />Longmont, Thornton and Westminster. As in 2004, all cities were analyzed as a whole as <br />well as individually, whenever possible. The Cities of Erie, Golden, and Thornton were <br />excluded from all parts of the analysis due to either incomplete or insufficient data. <br /> <br />Note for both 2004 and 2005 groups: <br />1) Data from the year the household received an inspection was not included. It was <br />not possible to account for changes in outdoor water use during the middle of the <br />growing season. Inspections were conducted throughout the summer, whereupon <br />narrowing down an exact date in which changes were made would be difficult. <br />2) All years analyzed were compared to ET for the corresponding year (as discussed <br />in the data processing section of this report). <br />3) All properties that had missing data for the years analyzed were excluded. <br />Missing data could be attributed to factors such as new construction, an <br />unoccupied property, incorrect meter reading (i.e. negative gallons), etc. <br />4) All properties that had negative outdoor inches for the years being analyzed were <br />excluded. Negative outdoor inches could be a result of incomplete annual data, <br />particularly incomplete data occurring during the summer months. It could also <br />be a result of incorrect meter readings (as mentioned above). <br />5) Records that indicated changes in property ownership during the study were <br /> <br />23 <br />