Urban and Regional Migration Estimates

Disclaimer: These
data are updated by the author and are not an official product of the Federal Reserve Bank of Cleveland.<br><br>This project provides two sets of migration estimates for the major US metro areas. The first series measures net migration of people to and from the urban neighborhoods of the metro areas. The second series covers all neighborhoods but breaks down net migration to other regions by four region types: (1) high-cost metros, (2) affordable, large metros, (3) midsized metros, and (4) small metros and rural areas. These series were introduced in a Cleveland Fed District Data Brief entitled “Urban and Regional Migration Estimates: Will Your City Recover from the Pandemic?"<br><br>The migration estimates in this project are created with data from the Federal Reserve Bank of New York/Equifax Consumer Credit Panel (CCP). The CCP is a 5 percent random sample of the credit histories maintained by Equifax. The CCP reports the census block of residence for over 10 million individuals each quarter. Each month, Equifax receives individuals’ addresses, along with reports of debt balances and payments, from creditors (mortgage lenders, credit card issuers, student loan servicers, etc.). An algorithm maintained by Equifax considers all of the addresses reported for an individual and identifies the individual’s most likely current address. Equifax anonymizes the data before they are added to the CCP, removing names, addresses, and Social Security numbers (SSNs). In lieu of mailing addresses, the census block of the address is added to the CCP. Equifax creates a unique, anonymous identifier to enable researchers to build individuals’ panels. The panel nature of the data allows us to observe when someone has migrated and is living in a census block different from the one they lived in at the end of the preceding quarter. For more details about the CCP and its use in measuring migration, see Lee and Van der Klaauw (2010) and DeWaard, Johnson and Whitaker (2019). <br><br><b>Definitions</b><br><br><b>Metropolitan area</b>The metropolitan areas in these data are combined statistical areas. This is the most aggregate definition of metro areas, and it combines Washington DC with Baltimore, San Jose with San Francisco, Akron with Cleveland, etc. Metro areas are combinations of counties that are tightly linked by worker commutes and other economic activity. All counties outside of metropolitan areas are tracked as parts of a rural commuting zone (CZ). CZs are also groups of counties linked by commuting, but CZ definitions cover all counties, both metropolitan and non-metropolitan. <br><b>High-cost metropolitan areas</b>High-cost metro areas are those where the median list price for a house was more than $200 per square foot on average between April 2017 and April 2022. These areas include San Francisco-San Jose, New York, San Diego, Los Angeles, Seattle, Boston, Miami, Sacramento, Denver, Salt Lake City, Portland, and Washington-Baltimore. <br><br><b>Other Types of Regions</b><br>Metro areas with populations above 2 million and house price averages below $200 per square foot are categorized as affordable, large metros. Metro areas with populations between 500,000 and 2 million are categorized as mid-sized metros, regardless of house prices. All remaining counties are in the small metro and rural category.<br><br>To obtain a metro area's total net migration, sum the four net migration values for the the four types of regions.<br><br><b>Urban neighborhood</b>Census tracts are designated as urban if they have a population density above 7,000 people per square mile. High density neighborhoods can support walkable retail districts and high-frequency public transportation. They are more likely to have the “street life” that people associate with living in an urban rather than a suburban area. The threshold of 7,000 people per square mile was selected because it was the average density in the largest US cities in the 1930 census. Before World War II, workplaces, shopping, schools and parks had to be accessible on foot. <br>Tracts are also designated as urban if more than half of their housing units were built before WWII and they have a population density above 2,000 people per square mile. The lower population density threshold for the pre-war neighborhoods recognizes that many urban tracts have lost population since the 1960s. While the street grids usually remain, the area also needs sufficient density to support neighborhood establishments and continue to function as an urban neighborhood. <br>Small cities and towns often have a few dense and walkable neighborhoods, but these tracts are not given an urban designation unless their metro area has at least 500,000 residents. Another defining characteristic of an urban neighborhood is that it places its residents close to amenities that can only be supported by the scale of a major metro, such as major league sports stadiums, professional theaters, museums, etc. <br><b>Urban migration</b>To obtain net urban migration estimates, we count the number of people moving into the urban neighborhoods of the indicated metros and subtract the number of people moving out of the same urban neighborhoods. Negative values mean more people are leaving than arriving. The out-migration counts include people moving from the urban neighborhoods to suburbs in the same metro area or to any region outside the metro area. Similarly, the in-migration counts include people arriving in the urban neighborhoods from suburbs in the same metro area or any region outside the metro area. Local urban-to-urban moves are not included. <br><b>Regional migration</b>The regional migration estimates count the people who move between different metro areas or between metro areas and rural commuting zones. Local within-metro movers are not included. The estimates of regional moves include everyone who moves to another region, making no distinction between urban/suburban neighborhoods.<br><br>Citation: If using the data, please cite Whitaker,
Stephan D. 2023. “Urban and Regional Migration Estimates: Will Your City
Recover from the Pandemic?” Federal Reserve Bank of Cleveland, Cleveland Fed
District Data Brief. https://doi.org/10.26509/frbc-ddb-20230803<br>
<br>The views expressed in this project description are those of the author and are not necessarily those of the Federal Reserve Bank of Cleveland or the Board of Governors of the Federal Reserve System.<br><br>

免责声明：本数据集由作者自行更新，并非克利夫兰联邦储备银行的官方产品。

本项目针对美国主要都市区提供两套人口迁移估算数据。第一套序列测算都市区城市社区间的人口净迁入与净迁出规模；第二套序列覆盖所有社区，并按四类区域类型划分跨区域净迁移：(1) 高成本都市区，(2) 经济型大型都市区，(3) 中型都市区，(4) 小型都市区与乡村区域。本数据集相关序列首次发布于克利夫兰联储区域数据简报《城市与区域迁移估算：你的城市能否从疫情中复苏？》。

本项目的迁移估算数据基于纽约联邦储备银行/艾可飞（Equifax）消费者信用面板（Consumer Credit Panel, CCP）构建。CCP是艾可飞维护的信用历史5%随机抽样样本，每季度可覆盖超1000万个人的居住普查小区信息。每月，艾可飞从债权人（抵押贷款机构、信用卡发卡方、助学贷款服务商等）处获取个人地址、债务余额及还款记录。艾可飞通过自研算法整合个人上报的所有地址，确定其最有可能的当前居住地址。在将数据纳入CCP前，艾可飞会对数据进行匿名化处理，移除姓名、地址及社会安全号码（Social Security Numbers, SSNs），仅保留地址对应的普查小区信息。艾可飞会生成唯一匿名标识符，以便研究人员构建个人面板数据。借助该数据的面板特性，我们可以观测到个人何时发生迁移，即其当前居住的普查小区与上一季度末的居住小区不一致的情况。如需了解CCP的更多细节及其在迁移测算中的应用，可参考Lee与Van der Klaauw（2010）以及DeWaard、Johnson与Whitaker（2019）的研究。

## 术语定义

### 都市区
本数据中的都市区采用组合统计都市区（Combined Statistical Areas）定义，这是最宏观的都市区分类标准，例如将华盛顿特区与巴尔的摩、圣何塞与旧金山、阿克伦与克利夫兰等合并归类。都市区由通勤及其他经济活动紧密关联的县组成。所有位于都市区之外的县均被纳入乡村通勤区（Commuting Zone, CZ）范畴。通勤区同样是由通勤关联的县组成的群体，其覆盖范围包含所有都市区与非都市区县。

### 高成本都市区
高成本都市区指2017年4月至2022年4月期间，住宅挂牌均价超过每平方英尺200美元的都市区，包括旧金山-圣何塞、纽约、圣地亚哥、洛杉矶、西雅图、波士顿、迈阿密、萨克拉门托、丹佛、盐湖城、波特兰以及华盛顿-巴尔的摩。

### 其他区域类型
人口规模超过200万且住宅均价低于每平方英尺200美元的都市区被归类为经济型大型都市区；人口规模介于50万至200万之间的都市区，无论住宅价格高低，均被归类为中型都市区；剩余所有县均归入小型都市区与乡村区域类别。

若要计算某都市区的总净迁移规模，只需将四类区域的净迁移数值相加即可。

### 城市社区
满足以下任一条件的普查片区（Census Tracts）将被划定为城市社区：其一，人口密度超过每平方英里7000人。高密度社区可支撑步行商业街区与高频次公共交通系统，更易具备人们印象中城市而非郊区的「街道活力」。选取每平方英里7000人的阈值，是因为该数值为1930年人口普查中美国最大城市的平均人口密度——二战前，工作场所、购物场所、学校与公园均需步行可达。其二，若普查片区内超半数住宅单元建于二战前，且人口密度超过每平方英里2000人，同样可被划定为城市社区。针对战前社区调低人口密度阈值，是考虑到自20世纪60年代以来，诸多城市社区的人口已出现流失。尽管街道网格大多保留，但区域仍需具备足够密度以支撑社区商业运营，并维持城市社区的功能。小型城镇往往拥有少量高密度、适宜步行的社区，但仅当其所属都市区人口至少达到50万时，这类社区才可被认定为城市社区。城市社区的另一核心特征是，其居民可便捷获取依托大都市规模才能支撑的公共服务设施，例如职业体育场馆、专业剧院、博物馆等。

### 城市迁移
城市净迁移规模的计算方式为，迁入指定都市区城市社区的人口数减去迁出该类社区的人口数。负值代表迁出人口多于迁入人口。迁出统计涵盖从城市社区迁往同都市区郊区或都市区外任意区域的人口；迁入统计涵盖从同都市区郊区或都市区外任意区域迁入城市社区的人口。同一都市区内的城市社区间迁移不计入统计。

### 区域迁移
区域迁移估算统计的是跨不同都市区，或都市区与乡村通勤区间的迁移人口，同一都市区内的通勤迁移不计入统计。区域迁移估算涵盖所有迁往其他区域的人口，不区分迁入地为城市社区还是郊区社区。

## 引用说明
若使用本数据集，请引用以下文献：Whitaker, Stephan D. 2023. 《城市与区域迁移估算：你的城市能否从疫情中复苏？》，克利夫兰联邦储备银行，克利夫兰联储区域数据简报。https://doi.org/10.26509/frbc-ddb-20230803

本项目描述中表达的观点仅代表作者本人，不一定代表克利夫兰联邦储备银行或美国联邦储备系统理事会的立场。