Open Data Tells NYC Residents Where the Rats Are 93
itwbennett writes "The New York City Health Department's Rat Information Portal provides raw data on where the rats are, based on inspections done by the health department, as well as by their rat indexing initiative. The portal isn't a new open data initiative, but if you're a NYC resident and not a big fan of rodents, the site is worth a look. 'The most interesting part of the portal is the interactive heat map of rat inspection data,' says ITworld's Phil Johnson. 'Using this interactive map, you can look up the inspection history, going back to 2009, for any address in the five boroughs. It will tell you the dates and results of any inspections, as well of any follow up compliance checks. As for raw data, the site provides city-wide rat reports, aggregated to the zip code level, going back to 2006.'"
Having spent many years dealing with environmental (Score:4, Informative)
and public health data, I'm always skeptical about datasets and maps like this. The reason is that what looks like a lot of data usually turns out to be not that much when you spread it out over all the environment you have to deal with. And it usually turns out to have all kinds of selection biases too -- at least the found stuff; data you collect as a side effect of other activities, rather than collected according to some kind of sampling protocol.
To see what I mean, look at the rodent heat map of NYC. You'll see red hot parcels adjacent to ice-cold parcels. Sometimes you'll have an ice-cold parcel with no reports surrounded on three sides by red hot parcels. Does that mean that one side of the boundary is teaming with rats and the other side has none whatsoever? Of course not. It means that somebody has reported a lot of rats on the "hot" parcel. Why is this? Well, maybe there's an observant resident. Maybe there's a place where it's particularly easy to see rats going about their business. Or maybe the residents of an area have banded together to generate a lot of reports so the city will do something. I've certainly seen stuff like that happen.
Imagine you are a rat looking at NYC. What are your top priorities? (1) water; (2) food, (3) shelter (or harborage in the rat watcher's lingo). And you're going to find those things *everywhere* in NYC. In fact the best places for you will be where you can go about your business unnoticed. There are many, many blocks with no rat reports surrounded by very similar blocks with lots of rat reports, and I'm guessing it's not because there are no rats there. And I doubt there's much more than a weak correlation between the rat population in an area and the number of reports.
Don't get me wrong. I think it's terrific NYC is making this data available. But I doubt you can conclude much about the rat population of your block from rat reports; it's safe to assume there are rats everywhere. If you want to know which blocks have the most rats, what you need is a field survey performed by experts.