8 ms·

How ZIP codes nearly masked the lead problem in Flint (2016)

113 points by dll 9y ago

brightball 9y ago
Has nobody in the conversation around the Flint crisis paid attention to Detroit Water's part in the issue? They terminated their contract when Flint decided it had long term plans to move and that termination forced the issue of finding an alternative water supply until the long term solution was ready. If not for that, there never would have been a problem, Flint would have eventually had its long term new supply without ever needing an intermediate option. When I sat down a finally looked over the details of this story it's the one glaring omission that I noticed from all of the news coverage.
- differentView 9y ago
  What's your point? Are you suggesting that Detroit Water is some how to blame?
  - brightball 9y ago
    Yep, at least partially. They terminated the contract.
- maxerickson 9y ago
  Detroit offered a reasonable long term contract before Flint started using the river water. http://www.metrotimes.com/news-hits/archives/2016/01/25/new-emails-reveal-the-switch-to-the-flint-river-was-not-about-saving-money http://www.metrotimes.com/news-hits/archives/2016/01/25/new-...
  - brightball 9y ago
    What I saw on CNN said that they offered a lower long term price as an alternative to Flint making the long term switch. When Flint announced it was making the long term switch, Detroit Water announced that they were terminating their contract which started a 1 year expiration clock. The permanent Flint solution wasn't due to be ready until a little over 2 years...which forced Flint to find an intermediate water supply. Detroit waters offer was only good if Flint agreed not to move essentially.
    - maxerickson 9y ago
      The low long term rate was only good for a long term contract. It's unlikely they refused to provide water in the interim. This article states they made a short term offer at a 10% price hike over the existing contract: http://www.detroitnews.com/story/news/michigan/flint-water-crisis/2016/02/02/late-bid-failed-avert-flint-detroit-water-deal/79735848/ http://www.detroitnews.com/story/news/michigan/flint-water-c... So Flint may have choose the river to save money (or not, it appears that the new system doesn't do that), they likely weren't in a pinch to actually be able to continue providing water.
      - brightball 9y ago
        Here's the CNN timeline: http://www.cnn.com/2016/03/04/us/flint-water-crisis-fast-facts/index.html http://www.cnn.com/2016/03/04/us/flint-water-crisis-fast-fac... > April 16, 2013 - On the city council's recommendation Andy Dillon, state treasurer, authorizes Flint to make the switch. One day later, the DWSD terminates its water service contract with Flint, effective April of 2014. There are further discussions, however, between Flint's leaders and the DWSD about options that would allow the city to purchase Detroit water after the contract ended. Flint resumes buying Detroit water in October of 2015. That termination the day after the announcement following a period of negotiation just screams retaliation when I read it.
- rhino369 9y ago
  As I understand it, the direct cause of the crisis wasn't that they changed water. It was they changed water and were totally incompetent in doing it. The basic PH levels in the new water are easily compensated for. Flint just didn't. It's like if an uber driver canceled your pick up and the next one you got was drunk driving. Sure that first driver was a but-for cause, but not a direct cause. They have no moral culpability for the reckless actions of the next person. edit: edited to correct the ph level as suggest by max.
  - maxerickson 9y ago
    The river water has too low of a ph, the correction is to increase it.
    - ceejayoz 9y ago
      Yep. And it wouldn't have cost much. Emphasis mine: > Marc Edwards, a professor at Virginia Tech who has been testing Flint water, says treatment could have corrected much of the problem early on — for as little as $100 a day — but officials in the city of 100,000 people didn't take action. > "There is no question that if the city had followed the minimum requirements under federal law that none of this would have happened," said Edwards, who obtained the Muchmore email through a Michigan Freedom of Information Act request. http://www.nbcnews.com/health/health-news/internal-email-michigan-blowing-flint-over-lead-water-n491481 http://www.nbcnews.com/health/health-news/internal-email-mic...
      - irixusr 9y ago
        Interesting. Although I tend to attribute things like this to ignorance and not malice. < Helps me pretend people aren't so bad. The people who make decisions often don't know what they're deciding about (how can the same person make a good decision about child education, policing standards and public hygiene?) and I think our modern philosophy that a "bad decision made early is better than no decision" amplifies this. There are some decisions in life that have to made carefully so we don't ask for forgiveness.
empath75 9y ago
A lot of people put far too much faith in algorithms, and assume that because it's all math, it's both correct and unbiased. There are so many, many ways to lie with numbers, and once money and power depend on the outcome of the algorithms, you can never trust that people won't design them to produce the outcomes they want. I suspect the problem here was less 'didn't understand geography' and more 'didn't give a shit about the truth'
tyingq 9y ago
This is an interesting read, but just seems like an obvious problem with no obvious solution other than "use the right boundaries for your problem space". He needed geographic search boundaries that matched where the suspect water was being delivered. It so happens in Flint's case that it matches city boundaries. I suspect that's not the case everywhere...that is water delivery in some places might extend beyond city boundaries. Or perhaps some cities are split, and have more than one water source. So the overall lesson here doesn't have much to do with zip codes, it has to do with searching the right boundaries. City boundaries wouldn't have been appropriate to search for mosquito borne issues. So that's not a good default either.
- maxerickson 9y ago
  The solution in the article was a simple scatterplot of the data points. There's no need to use any boundaries when just examining the data. The basically unbelievable thing that happened is that they only looked at one summary of the data.
  - tyingq 9y ago
    I agree with your last point. A scatter plot, though, could just reflect population density. There is still value in bounds so you can see relative figures. I don't see a silver bullet really. The difference here seemed to be having someone with the right skills.
    - maxerickson 9y ago
      Sure, it wouldn't be the end of the analysis or necessarily the thing you'd use to communicate the data. But here's a paragraph from the article about the distribution of the data: As I ran the addresses through a precise parcel-level geocoding process and visually inspected individual blood lead levels, I was immediately struck by the disparity in the spatial pattern. It was obvious Flint children had become far more likely than out-county children to experience elevated blood lead when compared to two years prior. "It was obvious"...
  - 9y ago
toast0 9y ago
At a more general level, your mailing address indicates how to deliver your mail; it does not indicate what city, if any, the delivery address is in. Neither does your zip code (as illustrated in the article), your phone number area code, or phone number prefix. All of these things indicate the location of the mail or phone facility that services the delivery address -- or that once did, before facility consolidation or expansion. A related phenomenon is that different agencies have different boundaries, despite often sharing the same geographic name. Cities, water districts, sanitary districts, school districts, community college districts, counties, congressional districts, etc each have their own boundaries, and they are usually not aligned.
- TallGuyShort 9y ago
  I encountered this the other day: friend of mine has a zip code associated with a major city, and puts the name of that city in their mailing address. But the land is not incorporated in any city. City government was trying to enforce city laws against them and use the mailing address as justification. Stupid.
  - deleted 9y ago
    [deleted]
  - bpicolo 9y ago
    Probably a part of the issue is that how zipcodes are defined is not actually publicly accessible information. You can pay private companies for it, sure.
    - baldeagle 9y ago
      I was going to point out that you can use R and tigris to get it, but that is only Zip Code Tabulation Areas, which don't map one-to-one to zip codes. Guess the Census Bureau and the USPS just can't get along.
      - maxerickson 9y ago
dsfyu404ed 9y ago
tl;dr Zip There isn't a good mapping between zip-code and water source so water source being the common denominator for high lead levels wasn't recognized, little additional effort was put into combing through the data and you know the rest of the story.
- sitkack 9y ago
  The flaw still exists anytime one is averaging data like this. Chicago is still tracking Blood Lead Levels at a ward level. It will completely miss a house with a contaminated feed pipe, because the house next to it will average out.
- foobarchu 9y ago
  The point isn't really about water boundaries, it's a larger about boundaries in general. Zip code isn't a good mapping to anything except how your mail is delivered. The water system was just a very good example of how using zip to do these mappings can fail catastrophically. This is a piece about GIS, not the particular data involved in telling it.
sitkack 9y ago
John Snow [1], who traced the cholera outbreak to an unsanitary water pump plotted the occurrences directly on a map. The other map in the article shows a similar flaw to that of using zipcodes. Lesson, if you want to correlate something spatially, use spatial coordinates. [1] https://en.wikipedia.org/wiki/John_Snow https://en.wikipedia.org/wiki/John_Snow
- cwmma 9y ago
  It's not really so simple, binning is a really useful technique to display data, especially large amounts of messy data. Just putting all the points on the map only works if you have a low enough number incidents in a compact enough area that the individual points make sense. But if you are not careful your points might actually be a population density map and be masking higher relative occurrences of something in certain areas. The key thing is that if your bins (zip codes) don't align well with the underlining data (municipalities) you can mask patterns. In this case they basically (to borrow a phrase from gerymandering) cracked the high led district across a bunch of zip codes. This is not actually an issue with zip codes nationwide, in MA there is only one zip code there crosses municipal boundaries so if you were doing the analysis in Massachusetts you wouldn't have had this issue.
  - will_pseudonym 9y ago
    You can easily bin spatial coordinates, too.
    - praseodym 9y ago
      Sure, but it still requires some more skill than say, creating an Excel PivotTable and drilling down on the ZIP column.
  - phonon 9y ago
    Make a Per Capita Heat Map. You can chart it in 5 minutes using Google Fusion Tables[1] or Excel with Power Map[2]. Both will even geocode addresses for you! [1] https://support.google.com/fusiontables/answer/1012281?hl=en https://support.google.com/fusiontables/answer/1012281?hl=en [2] https://support.office.com/en-us/article/Get-started-with-Power-Map-88a28df6-8258-40aa-b5cc-577873fb0f4a https://support.office.com/en-us/article/Get-started-with-Po...
kensey 9y ago
"ZIP codes were arbitrarily delineated and covered a range of neighborhood types; in most small and midsized cities, one ZIP code can cover urban, suburban and rural neighborhoods with highly variable socioeconomic characteristics." My own ZIP code is a perfect example of this. We're in the ZIP code of Town A, but Town B is actually the closest incorporated town to us. The Town A ZIP code extends between the state line and a river, up the eastern edge of our county. That covers our large development, which has people from very poor to very wealthy, four smallish unincorporated communities that are mostly poor-to-median, an incorporated town of about 1,000 bordering Town A, and the actual Town A which is a National Historical Park and consequently is mostly shops and museums catering to tourists and actually has very few residents (about 300 out of about 13000 that live in the ZIP code).
amichal 9y ago
Frustratingly the default guidance from HHS on preventing de-identification of PHI uses the first 3 digits of ZIP codes (ZCTAs actually) in their examples [1]. We've had fun conversations on publishing analyses that rolled up to other more useful spatial binning because of this. [1] https://www.hhs.gov/hipaa/for-professionals/privacy/special-topics/de-identification/#zip https://www.hhs.gov/hipaa/for-professionals/privacy/special-...
numo16 9y ago
The way the greater Flint area's zip codes and address system works out had some other interesting impacts, as well, from a business perspective. After the crisis became more public, we started seeing businesses who were in Flint (greater Flint area, Flint mailing address), but not the City of Flint (the affected area), putting up signs and trying to make very obvious that they didn't have Flint water. The City of Flint's water system is isolated from the rest of the county, which falls under the Genesee County Drain Commission's jurisdiction and is connected to the Detroit water system. It is still difficult to get some people to understand that they are different things (have had to explain to family many times that while we live in "Flint", we are not on Flint water). It would be interesting to see a study done on the effect this had on businesses both within the city and in the greater Flint area.
sarcher 9y ago
Great summation of the issue! ZIP code related issues are a constant problem. Often the administrators of data sets don't know how to geocode a full address, and there are few easy ways to have participants record 'good' geographies. Can you imagine asking people whether they know what Census Block they live in? So we end up with a lot of data sets where ZIP codes become bad short-hand for geography. Last year I worked on a study where the geographic data had been fuzzed prior to passing it along to the study team, a process that unfortunately resulted in the patient addresses being simplified to just the ZIP code provided by the patient. There were two major issues beyond the general unsuitability of ZIP codes as geography: first, ZIP codes don't seem to be verified during the course of patient care. They are recorded (incorrectly at a minimum rate of ~0.2%) as a part of a patient address during the creation of the initial record. Even if the address is used for mailings, a bad ZIP does not result in mis-delivered mail in the vast majority of cases due to the availability of city, state, and street address data in the full address. The issue is just never discovered until you are put into the position of relying on only the ZIP code for geography, at which point the mitigating data (the full address) is unavailable. Second, even when ZIP codes do match to Census ZCTAs (the closest thing to 'ZIP code geographies' available and commonly utilized) there are some ZIP codes that do not have exactly matching ZCTAs. For example, 03911 and 04565 are real ZIP codes without (exact) matching ZCTAs. It would be preferable if address data, before being obfuscated for data anonymity reasons, was properly geocoded. After geocoding, the resulting geography could then be fuzzed for anonymity. Of course, this would just lead to arguments about what constitutes proper diligence in geocoding :)
forkandwait 9y ago
I work for a social services agency, and my guesstimate is that 70% of the managers think that zip codes are the answer to all their spatial analysis problems -- they are very easy to collect, and they feel right. These managers don't really have any training in geography, so it isn't exactly surprising, but I think there is a pretty strong committment to zip codes as the unit of analysis because it is the one thing they know and think they understand. For the folks who in this thread say "just use a point map of occurrences and you would have seen the problem" you are right in this case, but it isn't really enough in most cases. For one, the boundary of the city limit needs to be shown to see the correlation; perhaps one should map the point occurrences a la Snow, and then overlay all the boundaries you have (mosquito district, city boundary, water district boundary, county, etc...). Additionally, a point map doesn't tell you rates of occurence, for that you need a denominator, or you can't calculate things like number of occurences divided by total population. One poster mentioned Census Tracts, and I would agree those should be the default boundary, subject to more investigation -- tracts correpsond well to "natural" boundaries, they are mostly consistent over census decades, they are mostly consistent with population (~5k), they nest perfectly with other census boundaries, and they are the smallest geography for which you can get mostly the full suite of population characteristics like education from the ACS. For some reason tracts feel just wrong to people. I have managers who reject zip codes, but then fixate on weird systems like pixels or equal area hexagons or whatever for which you can't get denominator data and which don't correspond to anything real. I don't understand, though I don't think in public policy / social work education anybody bothers to teach you shit about GIS or Census data unless you know to ask specifically.
haskal 9y ago
> guesstimate Stop making up words for which there already are words. "estimate" works just fine in that context.
- CommieBobDole 9y ago
  Guesstimate has been a word for 115 years. http://www.etymonline.com/index.php?allowed_in_frame=0&search=guesstimate http://www.etymonline.com/index.php?allowed_in_frame=0&searc...
- dang 9y ago
  Please don't be rude in comments here, or take threads on nitpicky tangents. We detached this subthread from https://news.ycombinator.com/item?id=14240636 https://news.ycombinator.com/item?id=14240636 and marked it off-topic.

113 points by dll 9y ago

Has nobody in the conversation around the Flint crisis paid attention to Detroit Water's part in the issue? They terminated their contract when Flint decided it had long term plans to move and that termination forced the issue of finding an alternative water supply until the long term solution was ready. If not for that, there never would have been a problem, Flint would have eventually had its long term new supply without ever needing an intermediate option. When I sat down a finally looked over the details of this story it's the one glaring omission that I noticed from all of the news coverage.

differentView 9y ago
What's your point? Are you suggesting that Detroit Water is some how to blame?
- brightball 9y ago
  Yep, at least partially. They terminated the contract.
maxerickson 9y ago
Detroit offered a reasonable long term contract before Flint started using the river water. http://www.metrotimes.com/news-hits/archives/2016/01/25/new-emails-reveal-the-switch-to-the-flint-river-was-not-about-saving-money http://www.metrotimes.com/news-hits/archives/2016/01/25/new-...
- brightball 9y ago
  What I saw on CNN said that they offered a lower long term price as an alternative to Flint making the long term switch. When Flint announced it was making the long term switch, Detroit Water announced that they were terminating their contract which started a 1 year expiration clock. The permanent Flint solution wasn't due to be ready until a little over 2 years...which forced Flint to find an intermediate water supply. Detroit waters offer was only good if Flint agreed not to move essentially.
  - maxerickson 9y ago
    The low long term rate was only good for a long term contract. It's unlikely they refused to provide water in the interim. This article states they made a short term offer at a 10% price hike over the existing contract: http://www.detroitnews.com/story/news/michigan/flint-water-crisis/2016/02/02/late-bid-failed-avert-flint-detroit-water-deal/79735848/ http://www.detroitnews.com/story/news/michigan/flint-water-c... So Flint may have choose the river to save money (or not, it appears that the new system doesn't do that), they likely weren't in a pinch to actually be able to continue providing water.
    - brightball 9y ago
      Here's the CNN timeline: http://www.cnn.com/2016/03/04/us/flint-water-crisis-fast-facts/index.html http://www.cnn.com/2016/03/04/us/flint-water-crisis-fast-fac... > April 16, 2013 - On the city council's recommendation Andy Dillon, state treasurer, authorizes Flint to make the switch. One day later, the DWSD terminates its water service contract with Flint, effective April of 2014. There are further discussions, however, between Flint's leaders and the DWSD about options that would allow the city to purchase Detroit water after the contract ended. Flint resumes buying Detroit water in October of 2015. That termination the day after the announcement following a period of negotiation just screams retaliation when I read it.
rhino369 9y ago
As I understand it, the direct cause of the crisis wasn't that they changed water. It was they changed water and were totally incompetent in doing it. The basic PH levels in the new water are easily compensated for. Flint just didn't. It's like if an uber driver canceled your pick up and the next one you got was drunk driving. Sure that first driver was a but-for cause, but not a direct cause. They have no moral culpability for the reckless actions of the next person. edit: edited to correct the ph level as suggest by max.
- maxerickson 9y ago
  The river water has too low of a ph, the correction is to increase it.
  - ceejayoz 9y ago
    Yep. And it wouldn't have cost much. Emphasis mine: > Marc Edwards, a professor at Virginia Tech who has been testing Flint water, says treatment could have corrected much of the problem early on — for as little as $100 a day — but officials in the city of 100,000 people didn't take action. > "There is no question that if the city had followed the minimum requirements under federal law that none of this would have happened," said Edwards, who obtained the Muchmore email through a Michigan Freedom of Information Act request. http://www.nbcnews.com/health/health-news/internal-email-michigan-blowing-flint-over-lead-water-n491481 http://www.nbcnews.com/health/health-news/internal-email-mic...
    - irixusr 9y ago
      Interesting. Although I tend to attribute things like this to ignorance and not malice. < Helps me pretend people aren't so bad. The people who make decisions often don't know what they're deciding about (how can the same person make a good decision about child education, policing standards and public hygiene?) and I think our modern philosophy that a "bad decision made early is better than no decision" amplifies this. There are some decisions in life that have to made carefully so we don't ask for forgiveness.

empath75 9y ago

A lot of people put far too much faith in algorithms, and assume that because it's all math, it's both correct and unbiased. There are so many, many ways to lie with numbers, and once money and power depend on the outcome of the algorithms, you can never trust that people won't design them to produce the outcomes they want. I suspect the problem here was less 'didn't understand geography' and more 'didn't give a shit about the truth'

tyingq 9y ago

This is an interesting read, but just seems like an obvious problem with no obvious solution other than "use the right boundaries for your problem space". He needed geographic search boundaries that matched where the suspect water was being delivered. It so happens in Flint's case that it matches city boundaries. I suspect that's not the case everywhere...that is water delivery in some places might extend beyond city boundaries. Or perhaps some cities are split, and have more than one water source. So the overall lesson here doesn't have much to do with zip codes, it has to do with searching the right boundaries. City boundaries wouldn't have been appropriate to search for mosquito borne issues. So that's not a good default either.

maxerickson 9y ago
The solution in the article was a simple scatterplot of the data points. There's no need to use any boundaries when just examining the data. The basically unbelievable thing that happened is that they only looked at one summary of the data.
- tyingq 9y ago
  I agree with your last point. A scatter plot, though, could just reflect population density. There is still value in bounds so you can see relative figures. I don't see a silver bullet really. The difference here seemed to be having someone with the right skills.
  - maxerickson 9y ago
    Sure, it wouldn't be the end of the analysis or necessarily the thing you'd use to communicate the data. But here's a paragraph from the article about the distribution of the data: As I ran the addresses through a precise parcel-level geocoding process and visually inspected individual blood lead levels, I was immediately struck by the disparity in the spatial pattern. It was obvious Flint children had become far more likely than out-county children to experience elevated blood lead when compared to two years prior. "It was obvious"...
- 9y ago

toast0 9y ago

At a more general level, your mailing address indicates how to deliver your mail; it does not indicate what city, if any, the delivery address is in. Neither does your zip code (as illustrated in the article), your phone number area code, or phone number prefix. All of these things indicate the location of the mail or phone facility that services the delivery address -- or that once did, before facility consolidation or expansion. A related phenomenon is that different agencies have different boundaries, despite often sharing the same geographic name. Cities, water districts, sanitary districts, school districts, community college districts, counties, congressional districts, etc each have their own boundaries, and they are usually not aligned.

TallGuyShort 9y ago
I encountered this the other day: friend of mine has a zip code associated with a major city, and puts the name of that city in their mailing address. But the land is not incorporated in any city. City government was trying to enforce city laws against them and use the mailing address as justification. Stupid.
- deleted 9y ago
  [deleted]
- bpicolo 9y ago
  Probably a part of the issue is that how zipcodes are defined is not actually publicly accessible information. You can pay private companies for it, sure.
  - baldeagle 9y ago
    I was going to point out that you can use R and tigris to get it, but that is only Zip Code Tabulation Areas, which don't map one-to-one to zip codes. Guess the Census Bureau and the USPS just can't get along.
    - maxerickson 9y ago

dsfyu404ed 9y ago

tl;dr Zip There isn't a good mapping between zip-code and water source so water source being the common denominator for high lead levels wasn't recognized, little additional effort was put into combing through the data and you know the rest of the story.

sitkack 9y ago
The flaw still exists anytime one is averaging data like this. Chicago is still tracking Blood Lead Levels at a ward level. It will completely miss a house with a contaminated feed pipe, because the house next to it will average out.
foobarchu 9y ago
The point isn't really about water boundaries, it's a larger about boundaries in general. Zip code isn't a good mapping to anything except how your mail is delivered. The water system was just a very good example of how using zip to do these mappings can fail catastrophically. This is a piece about GIS, not the particular data involved in telling it.

sitkack 9y ago

John Snow [1], who traced the cholera outbreak to an unsanitary water pump plotted the occurrences directly on a map. The other map in the article shows a similar flaw to that of using zipcodes. Lesson, if you want to correlate something spatially, use spatial coordinates. [1] https://en.wikipedia.org/wiki/John_Snow https://en.wikipedia.org/wiki/John_Snow

cwmma 9y ago
It's not really so simple, binning is a really useful technique to display data, especially large amounts of messy data. Just putting all the points on the map only works if you have a low enough number incidents in a compact enough area that the individual points make sense. But if you are not careful your points might actually be a population density map and be masking higher relative occurrences of something in certain areas. The key thing is that if your bins (zip codes) don't align well with the underlining data (municipalities) you can mask patterns. In this case they basically (to borrow a phrase from gerymandering) cracked the high led district across a bunch of zip codes. This is not actually an issue with zip codes nationwide, in MA there is only one zip code there crosses municipal boundaries so if you were doing the analysis in Massachusetts you wouldn't have had this issue.
- will_pseudonym 9y ago
  You can easily bin spatial coordinates, too.
  - praseodym 9y ago
    Sure, but it still requires some more skill than say, creating an Excel PivotTable and drilling down on the ZIP column.
- phonon 9y ago
  Make a Per Capita Heat Map. You can chart it in 5 minutes using Google Fusion Tables[1] or Excel with Power Map[2]. Both will even geocode addresses for you! [1] https://support.google.com/fusiontables/answer/1012281?hl=en https://support.google.com/fusiontables/answer/1012281?hl=en [2] https://support.office.com/en-us/article/Get-started-with-Power-Map-88a28df6-8258-40aa-b5cc-577873fb0f4a https://support.office.com/en-us/article/Get-started-with-Po...

kensey 9y ago

"ZIP codes were arbitrarily delineated and covered a range of neighborhood types; in most small and midsized cities, one ZIP code can cover urban, suburban and rural neighborhoods with highly variable socioeconomic characteristics." My own ZIP code is a perfect example of this. We're in the ZIP code of Town A, but Town B is actually the closest incorporated town to us. The Town A ZIP code extends between the state line and a river, up the eastern edge of our county. That covers our large development, which has people from very poor to very wealthy, four smallish unincorporated communities that are mostly poor-to-median, an incorporated town of about 1,000 bordering Town A, and the actual Town A which is a National Historical Park and consequently is mostly shops and museums catering to tourists and actually has very few residents (about 300 out of about 13000 that live in the ZIP code).

amichal 9y ago

Frustratingly the default guidance from HHS on preventing de-identification of PHI uses the first 3 digits of ZIP codes (ZCTAs actually) in their examples [1]. We've had fun conversations on publishing analyses that rolled up to other more useful spatial binning because of this. [1] https://www.hhs.gov/hipaa/for-professionals/privacy/special-topics/de-identification/#zip https://www.hhs.gov/hipaa/for-professionals/privacy/special-...

numo16 9y ago

The way the greater Flint area's zip codes and address system works out had some other interesting impacts, as well, from a business perspective. After the crisis became more public, we started seeing businesses who were in Flint (greater Flint area, Flint mailing address), but not the City of Flint (the affected area), putting up signs and trying to make very obvious that they didn't have Flint water. The City of Flint's water system is isolated from the rest of the county, which falls under the Genesee County Drain Commission's jurisdiction and is connected to the Detroit water system. It is still difficult to get some people to understand that they are different things (have had to explain to family many times that while we live in "Flint", we are not on Flint water). It would be interesting to see a study done on the effect this had on businesses both within the city and in the greater Flint area.

sarcher 9y ago

Great summation of the issue! ZIP code related issues are a constant problem. Often the administrators of data sets don't know how to geocode a full address, and there are few easy ways to have participants record 'good' geographies. Can you imagine asking people whether they know what Census Block they live in? So we end up with a lot of data sets where ZIP codes become bad short-hand for geography. Last year I worked on a study where the geographic data had been fuzzed prior to passing it along to the study team, a process that unfortunately resulted in the patient addresses being simplified to just the ZIP code provided by the patient. There were two major issues beyond the general unsuitability of ZIP codes as geography: first, ZIP codes don't seem to be verified during the course of patient care. They are recorded (incorrectly at a minimum rate of ~0.2%) as a part of a patient address during the creation of the initial record. Even if the address is used for mailings, a bad ZIP does not result in mis-delivered mail in the vast majority of cases due to the availability of city, state, and street address data in the full address. The issue is just never discovered until you are put into the position of relying on only the ZIP code for geography, at which point the mitigating data (the full address) is unavailable. Second, even when ZIP codes do match to Census ZCTAs (the closest thing to 'ZIP code geographies' available and commonly utilized) there are some ZIP codes that do not have exactly matching ZCTAs. For example, 03911 and 04565 are real ZIP codes without (exact) matching ZCTAs. It would be preferable if address data, before being obfuscated for data anonymity reasons, was properly geocoded. After geocoding, the resulting geography could then be fuzzed for anonymity. Of course, this would just lead to arguments about what constitutes proper diligence in geocoding :)

forkandwait 9y ago

I work for a social services agency, and my guesstimate is that 70% of the managers think that zip codes are the answer to all their spatial analysis problems -- they are very easy to collect, and they feel right. These managers don't really have any training in geography, so it isn't exactly surprising, but I think there is a pretty strong committment to zip codes as the unit of analysis because it is the one thing they know and think they understand. For the folks who in this thread say "just use a point map of occurrences and you would have seen the problem" you are right in this case, but it isn't really enough in most cases. For one, the boundary of the city limit needs to be shown to see the correlation; perhaps one should map the point occurrences a la Snow, and then overlay all the boundaries you have (mosquito district, city boundary, water district boundary, county, etc...). Additionally, a point map doesn't tell you rates of occurence, for that you need a denominator, or you can't calculate things like number of occurences divided by total population. One poster mentioned Census Tracts, and I would agree those should be the default boundary, subject to more investigation -- tracts correpsond well to "natural" boundaries, they are mostly consistent over census decades, they are mostly consistent with population (~5k), they nest perfectly with other census boundaries, and they are the smallest geography for which you can get mostly the full suite of population characteristics like education from the ACS. For some reason tracts feel just wrong to people. I have managers who reject zip codes, but then fixate on weird systems like pixels or equal area hexagons or whatever for which you can't get denominator data and which don't correspond to anything real. I don't understand, though I don't think in public policy / social work education anybody bothers to teach you shit about GIS or Census data unless you know to ask specifically.

haskal 9y ago

> guesstimate Stop making up words for which there already are words. "estimate" works just fine in that context.

CommieBobDole 9y ago
Guesstimate has been a word for 115 years. http://www.etymonline.com/index.php?allowed_in_frame=0&search=guesstimate http://www.etymonline.com/index.php?allowed_in_frame=0&searc...
dang 9y ago
Please don't be rude in comments here, or take threads on nitpicky tangents. We detached this subthread from https://news.ycombinator.com/item?id=14240636 https://news.ycombinator.com/item?id=14240636 and marked it off-topic.