basic care, conditions adverse to animal well‐being can result (e.g. high disease rates, numerous animals housed in small spaces or in carrying crates, dirty cages). It is often easy to recognize when a shelter is overcapacity or understaffed; quantitatively measuring overcrowding or deficits in staffing may be more difficult depending on the type and quality of data available but is worth the extra effort.
3.4.1 Housing Capacity
Why use metrics for monitoring housing capacity? This can be a valuable tool to reduce or avoid overcrowding. Common strategies for reducing overcrowding include increasing the number of housing units (either through construction or finding alternative housing sites), managing intake, and reducing the LOS. Building new housing is usually impractical and even when possible, will not resolve overcrowding if intake chronically exceeds the outflow of animals. The use of offsite adoption venues is also helpful but is rarely effective as the only approach to eliminating overcrowding; reducing the ALOS and/or managing the number of animals admitted over time are also approaches used by many shelters. The success of efforts to reduce ALOS at the population level is monitored as discussed previously. Similarly, efforts to reduce the number of incoming animals can be monitored over time using intake data.
The relationships between ALOS, intake, and the available housing space can be used to predict the effect of changing any one of these factors on the others over time (See the formula below). These predictions help set goals and motivate staff to achieve them.
During a specified period of time:
It is important to note that using this formula assumes that all humane housing spaces are occupied in the shelter at the beginning of a time period; it is used to calculate how many additional animals the shelter can expect to be able to provide humane housing for based on the number of spaces and the average length of stay.
To use the formula, a shelter must start by estimating the number of animals by species that can be humanely housed at any given time. The Guidelines for Standards of Care in Animal Shelters (Newbury et al. 2010) provide recommendations that may be used to determine which housing is humane. If the shelter experiences wide fluctuations in the number and/or age groups of animals entering by season, then the number that can be housed at any given time should be estimated by species, age group and by season. Counting the number of housing spaces is done making assumptions (e.g. two kittens or one adult cat per humane housing unit). (These numbers should be as accurate as possible but need not be perfect as they are used to generate estimates.
After estimating the number of available housing units, the shelter can acquire the ALOS for animals from its software system (by season and age group, if appropriate) and use those values to determine how many additional animals they can admit to the facility in that period of time while remaining within their humane housing capacity. Alternatively, the shelter can specify target ALOS values, depending on the intent of the calculations. The usefulness of the formula is illustrated in the following example. (Age group is ignored to simplify the calculations).
Shelter A historically receives an average of 260 cats during the months July–September (92 days), which results in some cats being euthanized and others being temporarily housed in stacked portable wire cages. The shelter has 40 humane housing spaces for cats and historically has had an ALOS during this period of 22 days per cat. The formula suggests that the shelter should only accept approximately 167 cats to avoid overpopulating during this period.
What would happen if the shelter reduced its ALOS? Looking at Table 3.3, if the shelter could reduce its ALOS to 14 days, it could successfully house an estimated 262 cats (enabling it to avoid overcrowding during the period). The shelter can make this ALOS a goal to work toward.
If the shelter also wished to manage its intake, it could modify the formula to estimate the number of cats (on average) that should be admitted daily during the period with a given ALOS. If both sides of the formula are divided by the number of days in the period, the average number of cats to be admitted daily can be estimated according to the modified formula below.
If the ALOS remained at 22 days, the shelter would need to reduce its weekly intake to approximately 12 (1.8 cats/day × 7 days) cats to avoid overpopulating (Column 4, Table 3.3). If the shelter were to reduce its ALOS to 18, they could comfortably accept 15 cats/week (2.9 cats/day × 7 days).
To summarize, the formula can be used to estimate the:
Table 3.3 The effect of lowering ALOS on the estimated number of cats that can be admitted during July–September without overcrowding in Shelter A.
| Number of housing units | Average LOS (days) | Cats that could be housed in the period | Approximate number of cats to accept |
|---|---|---|---|
| 40 | 22 | 167 | 1.8/day 12/week |
| 40 | 18 | 204 | 2.2/day 15/week |
| 40 | 14 | 262 | 2.9/day 20/week |
1 ALOS of animals needed to avoid overcrowding with a given intake and number of housing units;
2 number of animals to admit in a specified period based on the number of available housing units and ALOS;
3 predicted effect of reducing the ALOS on the number of animals that should be admitted to avoid overcrowding.
The formula can be used to estimate any one of its component parts (if the other values are known or target values are inserted). Thus, a shelter could also calculate the number of housing units needed to comfortably house animals with a specific ALOS and rate of intake. Additionally, this formula can be used to determine the number of animals to have on the adoption floor based on a specific ALOS in the adoption area and adoption rate (see the Adoption Driven Capacity calculator on the Koret Shelter Medicine website http://www.sheltermedicine.com/library/resources/capacity‐for‐care‐c4c‐magic‐number‐calculator). These uses, assumptions associated with the use of the formula, and the calculations are explained in more detail in other sources (Koret Shelter Medicine 2015; Newbury and Hurley 2013a; Scarlett et al. 2017c).
Other metrics can also be used to manage population numbers. For example, a shelter could compare the number of animals actually housed in the building (daily in‐shelter inventory) to the estimated number of available housing units. If the number of animals housed in the building exceeds the number of humane housing units available, the number of “excess animals” and the percent overcapacity could be monitored over time and strategies implemented to reduce it.
The use of the formula produces estimates because the component parts are estimated. Nonetheless, these estimates are tools that have helped manage the populations of a growing number of shelters, in combination with reducing ALOS, managing intake, improving the quality of housing and other approaches (Karsten et al. 2017).
3.4.2 Staffing Capacity
Inadequate staffing