Animal shelter data glossary
Plain-language definitions of the shelter data terms used on this site.
- Length of stay (LOS)
- Days from an animal's intake to its outcome. We count calendar days; same-day outcomes are 0. Shelter Animals Count defines it the same way, for animals that already have an outcome.
- Days in care
- How long an animal currently in the shelter has been there so far. Unlike LOS, it applies to animals still waiting for an outcome.
- Average daily population (ADP)
- The average number of animals in care on a given day. Average daily admissions × average length of stay.
- Capacity for care
- The number of animals a shelter can care for humanely at one time, given housing, staff, resources and available outcomes. See capacity for care, explained.
- Capacity for Care (C4C) model
- A population management approach from UC Davis Koret Shelter Medicine Program that sets a target daily population and manages stays to stay within it.
- Pathway planning
- Planning, at intake, the services an animal will need and the outcome it's headed toward, so steps happen without delay.
- Population rounds
- A regular (often daily) walk-through or meeting where staff review every animal's status, pathway and next steps.
- Median
- The middle value: half of animals left sooner, half later. Less affected by a few very long stays than the average.
- 90th percentile
- 9 in 10 animals left sooner than this. A good measure of the long tail of stays.
- Mean (average) stay
- Total days in care ÷ number of stays. Use it for cost and capacity math, because every day counts.
- Intake types
- How an animal arrived: stray, owner surrender, seized or held for custody, transfer in, returned adoption, return from foster, community cat / TNR, owner-requested euthanasia, public assist, born in care, or other.
- Outcome types
- How a stay ended: adoption, return to owner, transfer or rescue, return to field, foster placement, euthanasia, died in care, or other. We include every outcome type in benchmarks and models.
- Return to field (RTF)
- Healthy community cats who are sterilized, vaccinated and returned to where they were found.
- Foster placement
- An animal moving from the shelter to a foster home. Some shelters record this as an outcome, which ends that shelter stay in their data.
- Live release rate
- The share of outcomes that are live outcomes. Definitions vary; Shelter Animals Count publishes standard ones.
- Stray hold
- The legal waiting period for owners to reclaim a stray before other outcomes are possible. It sets a minimum stay for strays.
- Little's law
- A queueing rule: average number in a system = arrival rate × average time in the system. It's the math behind ADP.
- Censoring
- When recent animals haven't had time to reach an outcome yet. We leave out the last 180 days of intakes from benchmarks so long stays aren't undercounted.
- AUC
- A score from 0.5 (no better than a coin flip) to 1.0 (perfect) for how well a model ranks animals who will and won't have long stays.
- Calibration
- Whether predicted chances match reality: of animals given a 30% chance, about 30% should stay over 30 days.
- Time-based holdout
- Testing a model only on animals that arrived after all its training data, the way it will be used in practice.
- De-identified data
- Records with names, ID numbers, addresses and owner, adopter or finder details removed.
- Interrupted time series
- A before-and-after method that compares the months after a change to the trend from before, adjusting for season.