Concept: Return Migration

Introduction

This concept describes how Return Migration is operationalized for immigration-related research at MCHP. The concept includes the following sections:


• a brief definition,
  
• a list of Data Sources where the data comes from,
  
• a description of the Methods employed,
  
• links to Research Findings reported in MCHP publications,
  
• any Cautions / Limitations found during development of this concept, and
  
• a relevant SAS® code example in the SAS code and formats section.

Definition: return migration is a special type of emigration or outmigration in which an international immigrant or interprovincial migrant returns to their place of birth or last permanent residence.

Data Sources

The data used to produce this concept came from the following Repository databases:


• Manitoba Health Insurance Registry data
  
• Immigration Refugees and Citizenship Canada (IRCC) – Permanent Residence Database

Methods

In the deliverable. The Diversity of Immigrants to Manitoba, Migration Dynamics and Basic Healthcare Service Use by Urquia et al. (2020), return migration was operationalized as a new registration in the Manitoba Health Insurance Registry after having resided in Manitoba and leaving the province for at least 360 days, based on cancellation of coverage followed by a new registration. We calculated the return migration rate as the percent of people who left Manitoba and subsequently returned after more than 360 days.

The following describes the basic algorithm in developing the methodology for this concept. It summarizes the SAS® code example that is provided in the SAS code and formats section below.


1. create the immigrant cohort file from the IRCC crosswalk file for all immigrants found in Manitoba and sort by the unique IRCC identification number (IDNO);
   
2. create a landing file containing the arrival and landing dates from the two IRCC legacy and current landing files;
   
3. sort the landing file, and then merge with the immigrant cohort file using the unique IRCC identification number (IDNO);
   
4. sort the landing file by scrambled PHIN and landing date to identify and retain the earliest landing record per scrambled PHIN;
   
5. create a registry_coverage file using the MCHP REGCOV macro with a parameter for gapdays=360. Sort this file by scrambled PHIN, coverage start date and coverage end date;
   
6. merge the landing file with the registry_coverage file to identify coverage episodes during or after landing;
   
7. re-scan the Registry files to get the coverage added code (COVCODE) values for each episode (these are not retained by the REGCOV macro), and match these to the proper coverage episode by coverage start date;
   
8. keep coverage_code (COVCODE) value from second coverage episode, which will be used to resolve a return to Manitoba after a "cannot locate" value appears in the CANCCODE of the first episode during or after landing. The resulting filename is REGCOV;
   
9. keep one summary record of coverage episodes per individual scrambled PHIN, categorizing reasons for leaving (in the first episode) and returning (in the second), counting individuals with 2 or more coverage episodes as returned;
   
10. of those counted as returned, only count as a true return migration if the cancellation of their first coverage episode during or after landing was either due to leaving the province (to another province, territory or country), or due to a “cannot locate” value followed by a coverage added code in the second episode indicating a new resident from another province, territory or country; ;
    
11. keep one record per individual scrambled PHIN, categorizing the reason for leaving and returning;
    
12. produce output tables summarizing out/remigration counts by landing year and reason.

Research Findings

In the deliverable. The Diversity of Immigrants to Manitoba, Migration Dynamics and Basic Healthcare Service Use by Urquia et al. (2020), they investigated return migration in Manitoba.

Please see the following information reported in the on-line deliverable:


• discussion on Return Migration ;
  
• Table 3.3: Return Migration Rates for Immigrants to Manitoba by Reason for Coverage Cancellation and Landing Year, 1985-2017 - All ages ;
  
• Figure 3.21: Return Migration Rates for Immigrants, Interprovincial Migrants and All Other Manitobans by Reason for Coverage Cancellation and Coverage Start Decade, 1970-2019 - Coverage start on or after landing, January 1, 1970-March 31, 2019*, all ages**
  
• Appendix Table 5.1: Retention, Outmigration, and Return Migration Counts for Immigrants to Manitoba by Landing Year, 1985-2017 - All ages
  
• Appendix Figure 6.3: Return Migration Rates in Groups 1-11 by Reason for Coverage Cancellation - Coverage start on or after landing, January 1, 1970-March 31, 2019*, all ages**
  
• Appendix 2: Study Cohort and Comparison Groups 1-11

Cautions / Limitations

The following limitations were identified during development of this concept:


• Those individuals who could not be located have likely moved out of the province, but we do not have the data to determine this. We assume that if a "cannot locate" status code is followed in the next coverage episode by a coverage added code indicating a new resident from another province or territory of Canada, or another country, then the person had indeed left the province and returned.