Editing ZIP Code (section)

== Other uses ==
=== Delivery services ===
Delivery services other than the USPS, such as [[FedEx]], [[United Parcel Service]], and [[DHL]], require a ZIP Code for optimal internal routing of a package.<ref>{{Cite web|url=https://faq.usps.com/s/article/ZIP-Code-The-Basics|title=USPS.com FAQs|website=faq.usps.com|access-date=2019-02-21|archive-url=https://web.archive.org/web/20190222151852/https://faq.usps.com/s/article/ZIP-Code-The-Basics|archive-date=2019-02-22|url-status=dead}}</ref>

=== Statistics ===
{{As of|October 2019}}, there are 41,702 ZIP Codes in the United States.<ref>{{Cite web|url=https://greatdata.com/product/zip-code-database|title=ZIP Codes|archive-url=https://web.archive.org/web/20191019150049/https://greatdata.com/product/zip-code-database|archive-date=19 October 2019|url-status=dead}}</ref> Due to convenience, ZIP Codes are used not only for tracking of mail, but also commonly for gathering geographical statistics in the United States by some researchers.<ref name="Grubesic1">{{cite journal |last1=Grubesic |first1=Tony H |last2=Matisziw |first2=Timothy C |title=On the use of ZIP codes and ZIP code tabulation areas (ZCTAs) for the spatial analysis of epidemiological data |journal=International Journal of Health Geographics |date=2006 |volume=58 |issue=5 |page=58 |doi=10.1186/1476-072X-5-58|doi-access=free |pmid=17166283 |pmc=1762013 }}</ref><ref name="Chen1">{{cite journal |last1=Xiang |first1=Chen |last2=Ye |first2=Xinyue |last3=Widener |first3=Michael J. |last4=Delmelle |first4=Eric |last5=Kwan |first5=Mei-Po |last6=Shannon |first6=Jerry |last7=Racine |first7=Elizabeth F. |last8=Adams |first8=Aaron |last9=Liang |first9=Lu |last10=Jia |first10=Peng |title=A systematic review of the modifiable areal unit problem (MAUP) in community food environmental research |journal=Urban Informatics |date=27 December 2022 |volume=22 |issue=1 |doi=10.1007/s44212-022-00021-1|doi-access=free |bibcode=2022UrbIn...1...22C }}</ref> ZIP Codes are not created for statistical analysis, and thus their use for statistical analysis is heavily criticized for numerous reasons and advised against as a cartographic practice.<ref name="Chen1"/><ref name="Adams1">{{cite journal |last1=Adams |first1=Aaron |last2=Chen |first2=Xiang |last3=Li |first3=Weidong |last4=Zhang |first4=Chuanrong |title=Normalizing the pandemic: exploring the cartographic issues in state government COVID-19 dashboards |journal=Journal of Maps |date=27 Jul 2023 |volume=19 |issue=3 |pages=1–9 |doi=10.1080/17445647.2023.2235385|doi-access=free |bibcode=2023JMaps..19Q...1A }}</ref> As ZIP Codes are not polygons, but collections of mail routes and points, they are unsuitable for publication or distribution of most data.<ref name="Census Bureau1">{{cite web |title=ZIP Code Tabulation Areas (ZCTAs) |url=https://www.census.gov/programs-surveys/geography/guidance/geo-areas/zctas.html |website=U.S. Census Bureau |access-date=26 August 2023 |archive-date=August 26, 2023 |archive-url=https://web.archive.org/web/20230826203531/https://www.census.gov/programs-surveys/geography/guidance/geo-areas/zctas.html |url-status=live }}</ref> Polygons for ZIP Codes are not released by the USPS and instead interpolated by 3rd party vendors.<ref name="Grubesic1" /> These interpolations introduce topological errors and are not standard between vendors.<ref name="Grubesic1" /> The USPS often discontinues, splits, or otherwise modifies ZIP Codes, making continuous space-time analysis challenging, leading to issues with both the [[modifiable areal unit problem]] (MAUP) and [[modifiable temporal unit problem]] (MTUP).<ref name="Grubesic1" /><ref name="Adams1"/> As the ZIP Codes are postal routing numbers, individuals and organizations without concrete spatial locations may be given a number, making it impossible to associate demographic data with them.<ref name="Grubesic1" /> Demographic data is inconsistent between ZIP Codes, and no effort is made to ensure they are proper enumeration units for analysis.<ref name="Grubesic1" /> As ZIP Codes are not made with the same considerations as other enumeration units, and is not possible without committing the [[ecological fallacy]].<ref name="Grubesic1" /><ref name="Chen1"/> This again becomes an issue with the MAUP. They have been found not to have significant correlations with health indicators, which can lead to poor conclusions.<ref name="Chen1"/> Despite these issues, ZIP Codes remain popular among researchers in fields such as public health due to their convenience, public familiarity with them, ability to anonymize subject addresses through aggregation, and possible ignorance of more appropriate enumeration units on the part of researchers.<ref name="Grubesic1" /><ref name="Adams1" />

In an attempt to satisfy demand "by data users for statistical data by ZIP Code area", the [[United States Census Bureau|U.S. Census Bureau]] calculates approximate boundaries of ZIP Code areas, which it calls [[ZIP Code Tabulation Area]]s (ZCTAs).<ref name="Census Bureau1" /><ref name="Grubesic1" /> Statistical census data is then provided for these approximate areas. The geographic data provided for these areas includes the [[latitude]] and [[longitude]] of the center-point of the ZCTAs. ZIP Codes are inherently discrete or ''point-based'' data, as they are assigned only at the point of delivery, not for the spaces between the delivery points. The United States Census Bureau then interpolates this discrete data set to create polygons by attempting to match ZIP Code extents with Census blocks.<ref name="Grubesic1" /> The resulting aereal units represent the approximate extent of the ZIP Code, which are combined to use for mapping and data presentation. The process of creating ZCTAs and their use for statistical analysis is heavily criticized in the literature. First, the creation of ZCTAs from Census blocks encounters issues when a Census block straddles multiple ZIP Codes.<ref name="Grubesic1" /> Addressing this is another instance of the MAUP, and the solution of dividing aggregate units between ZIP Codes causes some individuals to fall into ZCTAs that do not match their ZIP Code.<ref name="Grubesic1" /> The creation of these units is therefore committing the [[ecological fallacy]] by attempting to disaggregate aggregate data. As ZIP Codes are not continuous, not everyone in the United States has one; there are ZIP Codes for non-populated or geographic areas, resulting in there not being one ZCTA for every ZIP Code.<ref name="Grubesic1" /> ZCTAs are not updated as frequently as the USPS updates ZIP Codes, resulting in further temporal analysis issues when ZIP Codes change during a study period.<ref name="Grubesic1" /> Datasets providing a similar approximate geographic extent to ZCTA are commercially available. Despite these issues, ZCTAs are still very popular with researchers in fields like epidemiology, and among government agencies, with some states employing them to publish and distribute public health data during the COVID-19 pandemic.<ref name="Adams1" />

=== Marketing ===
The data is often used in [[Advertising mail|direct mail marketing]] campaigns in ZIP-code marketing. [[Point of sale|Point-of-sale]] cashiers sometimes ask consumers for their home ZIP Codes. Besides providing purchasing-pattern data useful in determining the location of new business establishments, retailers can use directories to correlate this ZIP Code with the name on a credit card to obtain a consumer's full address and [[telephone number]]. ZIP-Coded data are also used in analyzing geographic risk factors, an insurance and banking industry practice pejoratively known as [[redlining]]. This can cause problems, ''e.g.'', expensive insurance, for people living near a town with a high crime rate and sharing its ZIP Code, while they live in a relatively crime-free town.

California outlawed this practice in 2011.<ref>{{Cite news | title=California high court: Retailers can not request cardholders' ZIP Code | url=http://www.cnn.com/2011/US/02/10/california.credit.zip.code/index.html | last=Botelho | first=Greg | publisher=CNN | date=February 10, 2011 | access-date=February 11, 2011 | archive-date=November 10, 2012 | archive-url=https://web.archive.org/web/20121110023619/http://www.cnn.com/2011/US/02/10/california.credit.zip.code/index.html | url-status=live }}</ref>

=== Legislative districts ===
ZIP Codes may not currently be used to identify existing legislative districts. Although the website of the [[United States House of Representatives]] has a "Find Your Representative" feature that looks up congressional districts based on ZIP Codes alone, it often returns multiple districts corresponding to a single ZIP Code.<ref>{{Cite web|url = http://www.house.gov/|title = The United States House of Representatives · House.gov|access-date = January 26, 2010|archive-date = September 24, 2010|archive-url = https://web.archive.org/web/20100924145826/http://baic.house.gov/|url-status = live}}</ref><ref>{{Cite web|url = http://www.house.gov/representatives/find/|title = Find Your Representative · House.gov|access-date = July 8, 2014|archive-date = July 8, 2014|archive-url = https://web.archive.org/web/20140708212246/http://www.house.gov/representatives/find/|url-status = live}}</ref> This is because different parts of one ZIP Code can be in different districts.<ref>{{Cite web|url = http://sunlightfoundation.com/blog/2012/01/19/dont-use-zipcodes/|title = Sunlight Foundation|date = Jan 19, 2012|access-date = Aug 6, 2014|archive-url = https://web.archive.org/web/20140813005420/http://sunlightfoundation.com/blog/2012/01/19/dont-use-zipcodes/|archive-date = August 13, 2014|url-status = dead}}</ref> One proposal to eliminate the possibility of extreme partisan [[gerrymandering]] calls on using ZIP Codes as the basic units for redistricting.<ref>{{Cite web |last1=Steelman |first1=Tyler |last2=Curiel |first2=John |title=Here's one way to end partisan gerrymandering: Don't break up Zip codes |url=https://www.washingtonpost.com/news/monkey-cage/wp/2018/10/22/heres-one-way-to-end-partisan-gerrymandering-dont-break-up-zip-codes/ |website=Monkey Cage blog |publisher=Washington Post |access-date=4 November 2018 |date=October 22, 2018 |archive-date=November 5, 2018 |archive-url=https://web.archive.org/web/20181105012125/https://www.washingtonpost.com/news/monkey-cage/wp/2018/10/22/heres-one-way-to-end-partisan-gerrymandering-dont-break-up-zip-codes/ |url-status=live }}</ref>

=== Internet ===
A 1978 proposal for a nationwide system of community networks suggested using ZIP Codes for [[routing]].<ref name="wilber197802">{{Cite news | url=https://archive.org/stream/byte-magazine-1978-02/1978_02_BYTE_03-02_Hardware_Projects#page/n15/mode/2up | title=CIE Net: A Design for a Network of Community Information Exchanges | work=BYTE | date=February 1978 | access-date=17 October 2013 | author=Wilber, Mike | page=12}}</ref>

ZIP Code data is an integral part of dealer / [[Online locator service|store locator]] software on many [[website]]s, especially [[Bricks and clicks|brick-and-click]] websites. This software processes a user-input ZIP Code and returns a list of store or business locations, usually in the order of increasing distance from the center of the input ZIP Code. As the ZIP Code system is confined to the U.S. Postal network, websites that require ZIP Codes cannot register customers outside the United States. Many sites will purchase postal code data of other countries or make allowances in cases where the ZIP Code is not recognized.{{citation needed|date=March 2022}}

ZIP Codes are regularly used on the Internet to provide a location where an exact address is not necessary (or desirable) but the user's municipality or general location is needed. Examples (in addition to the store locator example listed above) include weather forecasts, television listings, local news, and [[Online dating service|online dating]] (most general-purpose sites, by default, search within a specified [[radius]] of a given ZIP Code, based on other users' entered ZIP Codes).

=== Credit card security ===
{{Main|Address Verification System}}

ZIP Codes are used in credit card authorization, specifically [[Address Verification System]] (AVS). When a merchant collects the entire address, the ZIP Code is an important part of AVS. In some cases, the ZIP Code is the only thing used for AVS, specifically where collecting a signature or other information is infeasible, such as [[pay at the pump]] or [[vending machine]]s.{{citation needed|date=March 2022}}