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On January 25 and 26 from 9:00 to 16:00h, Lisa Johnston will be hosting a two-day masterclass at the University of Amsterdam on survey techniques for hidden and hard-to-reach populations.

Dr Lisa Johnston

Because most hard-to-reach populations do not have sampling frames from which to draw a probability sample, researchers often rely on convenience sampling methods, resulting in data this are unrepresentative and with unmeasureable biases. Respondent driven sampling (RDS) and time location sampling (TLS) have been highlighted as robust and effective methods to recruit large samples (100+) of populations with no sampling frames and considered hard-to-reach for research purposes. RDS relies on sampling populations that are connected through social networks and TLS relies on sampling populations that can be recruited from mapped and randomly selected venues.

This two day workshop will introduce the theories and processes for implementing and analyzing data using RDS and TLS. The main focus of this workshop will be on RDS, since this is the method currently used most widely and has a more complex analysis component based on Markov chain and biased network theories, where estimates are adjusted using each participant’s social network size and information about who recruited whom. RDS has been used successfully to gather quantitative data on the standards of work and living among migrant populations, salaries and union membership among jazz musicians, political affiliations and life experiences among war veterans, injecting behaviors among people who inject drugs, sexual risk among sex workers, school enrollment and income earning among youth who live on the streets, partnerships among men who have sex with men, pregnancies related to sexual violence among women in the Congo, and numerous other outcomes among populations that are networked through political and other social affiliations.

About Lisa Johnston:

Dr. Lisa Johnston has over 11 years of experience providing training and technical support to academics and policymakers. She is affiliated with Tulane University, School of Public Health and Tropical Medicine and the University of California, San Francisco, Global Health Sciences. Her CV is available here:


Please contact Mike Nicholson ( if you are interested in participating.