Does Size Really Matter? A Sensitivity Analysis of the Number of Seeds in a Respondent-Driven Sampling Study of GBM in Vancouver, Canada

What is the importance of this study? ¥ While there is an estimate of the number of gay, bisexual and other men who have sex with men (GBM) in Vancouver, it is difficult to get a diverse and representative sample. ¥ Previous researchers have found certain sub-populations may be underrepresented in research data.

Citation: Lachowsky NJ, Sorge JT, Raymond HF, Cui Z, Sereda P, Rich A, Roth EA, Hogg RS, Moore DM. Does size really matter? A sensitivity analysis of number of seeds in a respondent-driven sampling study of gay, bisexual and other men who have sex with men in Vancouver, Canada. BMC Medical Research Methodology. 2016 Nov 16;16(1):157.

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During the Canada Post strike announced September 25, 2025, the following measures will be undertaken to minimize service disruption to BC-CfE clients and providers.

  • The BC-CfE Laboratory has transitioned to private courier for delivery of outgoing reports and documents. Results required urgently can be faxed upon request. (Lab Contact Information: Phone 604-806-8775; FAX 604-806-9463)
  • The BC-CfE Drug Treatment Program (DTP) will fax outgoing forms and documents to the provider’s office. (DTP Contact Information: Phone 604-806-8515; FAX 604-806-9044)
  • St. Paul’s Hospital Ambulatory Pharmacy has transitioned to private courier for delivery of medications. We recommend requesting medication at least 2 weeks in advance in case of delivery delays, particularly to rural/remote parts of BC. (Contact Information: Phone 1-800-547-3622; FAX 604-806-8675)

During the Canada Post strike, we recommend that documents be faxed or couriered to our sites, versus utilization of regular mail service

The BC-CfE Laboratory is streamlining reporting processes for certain tests in order to simplify distribution and record-keeping, and to ensure completeness of results. Beginning September 2, 2025, results for the ‘Resistance Analysis of HIV-1 Protease and Reverse Transcriptase’ (Protease-RT) and ‘HIV-1 Integrase Resistance Genotype’ tests will be combined into a single ‘HIV-1 Resistance Genotype Report’.
For more details and example reports, please click on the button below