We have received some good questions about whether or not a given observation should qualify for inclusion in the project. To make our rules more explicit, we're outlining them here. If you are still unsure whether your observation qualifies, feel free to ask in the comments below.

RULES
The goal of this project is to identify the non-captive/non-cultivated species that can be found in a newly formed ecosystem: the interior of human habitations.

1. Be in a habitation: a habitation is any structure built by people with walls and a roof. In many regions, such habitations are relatively impermeable to, say, rat-sized organisms, but in some regions, habitations are more open. Since it’s a “habitation,” people have to be in it, at least occasionally, so structures that have been abandoned for years don't count. At the same time, portions of habitations rarely entered by people but closely associated with places we do enter (the attic or crawlspace of a home, the space beneath floorboards etc.) should count. This definition is inclusive of most traditional habitations (mud brick, thatch-roof, etc.) as well, which, while more permeable to the outside than drywall and shingles, are still mostly self-contained.

2. Be in the interior: the "interior” means the organism can’t just be on the exterior walls, or in close proximity to the structure. It has to be inside the threshold.

3. Must be found in: There are two groups of indoor organisms: those that are exploiting resources inside and making indoor living a facet of their natural history (i.e., “residents”) and those that happen into the indoors (i.e., “tourists”). The first group is particularly relevant to questions of adaptation and evolution, while the latter group includes organisms relevant to human experience and disease exposure. For Never Home Alone, we are interested in both groups. This is partly a result of the fact that the boundary between these groups is fuzzy. In addition, it is very challenging to discern which group an organism is in based solely on a photo (e.g., are the dead flies on the windowsill trapped tourists or did they pupate from fruit in the cupboard, mate, and then die, having passed on their genes?) Thus, any observation of an organism indoors that wasn’t deliberately brought indoors by people should count, even if that organism doesn’t seem to “want” to be inside.

4. Must be non-captive/non-cultivated: Basically no pets/houseplants. Observation doesn’t necessarily have to follow iNaturalist’s definition of “wild,” which says that “wild” organisms are independently surviving/reproducing. That is, a non-native species that enters the home via a box of fruit would not be considered “wild” by iNaturalist if there were no records of it having a successfully reproducing population in that area. We would still want such an observation for Never Home Alone, even if iNaturalist doesn’t consider it to be wild.

FAQs
Do pets/potted plants qualify?
No

Do wild organisms associated with pets/potted plants qualify (e.g., fleas, flies hatching from potting soil, etc.)?
Yes

Does the observation have to be in a house, specifically?
No, other human habitations like offices, warehouses, airports, hotels etc. also qualify

Do observations in gardens, porches, streets, and other outdoor areas qualify?
No, these observations are not indoors

Do observations of organisms brought inside by humans qualify (e.g., a dragonfly that landed on your backpack during a hike, that you inadvertently brought inside)?
Observations of organisms deliberately brought inside by people do not count (e.g., a bug you brought inside to get better light for a photo), though I suppose there could be an edge case where people routinely bring certain organisms inside in such a way that it’s a part of the indoors experience. Observations of organisms inadvertently brought inside by people should generally count (e.g., worms in your apples), though there are likewise probably exceptions (a dragonfly that landed on your backpack during a hike, that you inadvertently brought inside isn’t really in the spirit of the project).

Do organisms on the exterior walls of a habitation qualify?
No, these observations are not indoors

Do interior courtyards qualify?
Not if the courtyard is open air (open to the sky)

Do traditional home types (mud brick, grass thatch roof, etc.) qualify?
Yes. Perhaps note in the comments if the observation is from a traditional home type

Do molds/fungi qualify (e.g. fungal infections of citrus fruits)?
Yes, similar situation to fleas

Do attics, basements, crawlspaces, sheds, outhouses etc. qualify?
Yes, they are indoor extensions of the primary human habitation even if people rarely enter them

Do garages qualify?
If the garage is usually closed then yes, if it’s mostly open then no

Do RVs/other “motorized habitations” qualify?
Yes

Do observations from greenhouses qualify?
The plants in the greenhouse do not qualify (they are captive/cultivated). Wild organisms associated with those plants (lizards, snails, etc.) do qualify, but please note in the comments if the observation comes from a greenhouse (large greenhouses are rather different from the typical human habitations we are interested in)

Do observations from a barn qualify?
Most barns are permeable enough that we wouldn’t consider them a habitation, as defined above

Do plants qualify?
Almost never. A few users have submitted observations of fish tank algae, which do qualify. But situations in which a wild plant is growing indoors would seem exceptionally rare. A user did note that you sometimes get weeds in greenhouses. I suppose a greenhouse weed would qualify.

Do insects that were collected outside but were brought inside to be pinned and stored in a collection qualify?
Definitely not!