Introduction

This concept describes how Retention (related to immigration / 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: Retention is the ability of a province to retain the immigrants (internal and international) it has attracted within a defined period, usually three or five years. The retention rate is the proportion of newcomers to the province that are found still residing three or five years after the first start of coverage for interprovincial migrants, and the later of start of coverage or landing date for Immigrants.

Data Sources

The data used to operationalize 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), retention was operationalized by finding the landing date of immigrants living in Manitoba, reviewing the Manitoba Health Insurance Registry coverage episodes ending after landing, and then calculating the retention rate for permanent residents of Manitoba.

NOTE: retention rates are based on a snapshot of registry coverage after the period of time in question, and do not require continuous coverage for the entire period. An immigrant is considered to be retained if they are in the province at the end of that period of time beginning at the later of landing date or start of coverage, even if they left the province during that period and returned before the end of the period. For consistency with other migration dynamics analyses, we ignore coverage gaps of 360 days or less.

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. keep one summary record of coverage episodes per individual scrambled PHIN, checking for 3- and 5-year retention periods in any episode and ensuring they are within the study time period;
   
8. produce output tables summarizing 3- and 5-year retention rates by landing year.

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 retention and reported on the retention rates for immigrants to Manitoba.

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


• discussion on retention ;
  
• Table 3.2: Retention and Outmigration Rates for Immigrants to Manitoba by Landing Year, 1985-2017 - All ages
  
• Figure 3.19: Three- and Five-Year Retention Rates for Immigrants and Interprovincial Migrants by Coverage Start Decade, 1985-2019 - Three- and five-year periods from coverage start on or after landing*, January 1, 1985-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 6.1: Three- and Five-Year Retention Rates in Groups 1-4 and 7-8 - Three- and five-year periods from coverage start on or after landing*, January 1, 1970-March 31, 2019**, all ages

Cautions / Limitations

The following limitations were identified during development of this concept:


• Retention rates are based on a snapshot of registry coverage after the period of time in question, and do not require continuous coverage for the entire period. An immigrant is considered to be retained if they are in the province at the end of that period of time beginning at the later of landing date or start of coverage, even if they left the province during that period and returned before the end of the period. For consistency with other migration dynamics analyses, we ignore coverage gaps of 360 days or less.
  
• The threshold to measure retention varies in the literature. Users may need to perform their own literature review to justify a cut-off point.