ABS - Net Internal and Overseas Migration Estimates - by Age (GCCSA) 2017-2020

This dataset presents the estimates of the internal and overseas migration statistics of Australia by age by Greater Capital City Statistical Area (GCCSA) following the 2016 Australian Statistical Geography Standard (ASGS). The dataset spans from the 2016-17 financial year up to the 2019-20 financial year.\n\nOverseas migration is the movement of people from overseas to Australia's sub-state areas and vice-versa. It cannot be directly measured and is estimated by breaking down overseas migrant arrivals and departures at the state level to sub-state areas, using information from the most recent Census. The state-level overseas migration data is sourced from Department of Home Affairs processing systems, visa information, and incoming passenger cards, and is published in [National, state and territory population](https://www.abs.gov.au/statistics/people/population/national-state-and-territory-population/latest-release).\n\nInternal migration is the movement of people across a specified boundary within Australia involving a change in place of usual residence. It cannot be directly measured and is instead estimated using administrative data. The movement of people between and within Australia's states and territories cannot be directly measured and is estimated using administrative data. Internal migration is estimated based on a combination of Census data (usual address one year ago), Medicare change of address data (provided by Services Australia), and Department of Defence records (for military personnel only). \n\nThe Medicare source data is assigned to a state or territory and GCCSA for a person's departure and arrival locations, based on the postcodes of their residential addresses as registered with Medicare. Postcodes are assigned wholly to a state/territory and GCCSA based on best fit. Where a postcode is split across areas, it is assigned to the area that contains the majority of that postcode's population.\n\nFor more information please visit the [Regional population methodology](https://www.abs.gov.au/methodologies/regional-population-methodology/2019-20).\n\n AURIN has spatially enabled the [original data](https://explore.data.abs.gov.au/vis?tm=migration&pg=0&df[ds]=ABS_ABS_TOPICS&df[id]=ABS_REGIONAL_MIGRATION&df[ag]=ABS&df[vs]=1.0.0&pd=%2C&dq=9%2B6.GCCSA...A&ly[rs]=AGE&ly[rw]=ASGS_2016&ly[cl]=MIG_TYPE%2CTIME_PERIOD).

本数据集基于2016年澳大利亚统计地理标准（Australian Statistical Geography Standard, ASGS），呈现了澳大利亚按年龄及更大首府城市统计区（Greater Capital City Statistical Area, GCCSA）划分的境内与境外移民统计估算值。数据集覆盖2016-17财年至2019-20财年。

境外移民指人员从境外前往澳大利亚州以下区域，以及反向流动的行为。该数据无法直接测量，需依托最新人口普查的相关信息，将州级境外移民入境与离境数据拆解至州以下区域以完成估算。州级境外移民数据来源于澳大利亚内政事务部（Department of Home Affairs）的处理系统、签证信息及入境旅客登记卡，相关数据已发布于《全国、州及领地人口》(https://www.abs.gov.au/statistics/people/population/national-state-and-territory-population/latest-release)。

境内移民指人员在澳大利亚境内跨越指定边界且变更常驻地的流动行为。该数据无法直接测量，需通过行政数据完成估算——澳大利亚各州及领地之间、各州/领地内部的人员流动均属于此类无法直接测量的范畴，最终通过行政数据进行估算。境内移民估算结合了三类数据：人口普查数据（过去一年常驻地信息）、澳大利亚服务部（Services Australia）提供的医保（Medicare）住址变更数据，以及澳大利亚国防部（Department of Defence）记录（仅针对军事人员）。

医保源数据会根据人员在医保系统登记的住宅地址邮编，将其分配至对应州/领地及GCCSA的出发与到达区域。邮编会按最优匹配原则完全划归至某一州/领地及GCCSA；若某邮编跨区域划分，则将其划归至覆盖该邮编多数人口的区域。

如需了解更多信息，请访问《区域人口方法论》(https://www.abs.gov.au/methodologies/regional-population-methodology/2019-20)。

澳大利亚城市与区域研究基础设施网络（Australian Urban and Regional Information Infrastructure, AURIN）已对[原始数据](https://explore.data.abs.gov.au/vis?tm=migration&pg=0&df[ds]=ABS_ABS_TOPICS&df[id]=ABS_REGIONAL_MIGRATION&df[ag]=ABS&df[vs]=1.0.0&pd=%2C&dq=9%2B6.GCCSA...A&ly[rs]=AGE&ly[rw]=ASGS_2016&ly[cl]=MIG_TYPE%2CTIME_PERIOD)完成空间赋能处理。