Smartphone-based Respondent Driven Sampling (RDS): A methodological advance in surveying small or ‘hard-to-reach’ populations

Abstract

Producing statistically robust profiles of small or ‘hard-to-reach’ populations has always been a challenge for researchers. Since surveying the wider population in order to capture a large enough sample of cases is usually too costly or impractical, researchers have been opting for ‘snowballing’ or ‘time-location sampling’. The former does not allow for claims to representativeness, and the latter struggles with under-coverage and estimating confidence intervals. Respondent Driven Sampling (RDS) is a method that combines snowballing sampling with an analytical algorithm that corrects for biases that arise in snowballing. For all its advantages, a major weakness of RDS has been around data collection. Traditionally done on-site, the process is costly and lengthy. When done online, it is cheaper and faster but under a serious threat from fraud, compromising data quality and validity of findings. This paper describes a real-life application of a RDS data collection system that maximizes fraud prevention while still benefiting from low cost and speedy data collection.

Remote Assessment in healthcare—Technologies, methods, benefits, and challenges

“…From a technological point of view, remote assessment is often associated with the use of telephones, smartphones, video, or web-based technologies. This is also evident in this collections, where most studies use video/phone consultation [ 4 ], web-based systems [ 1 , 5 – 7 ], or smartphones [ 2 , 10 ]. Interestingly, however, a few of the included studies also involve remote assessment using medical devices.…”

“…The papers in the collection address a wide spectrum of health topics including mental health [ 1 , 10 ], cognitive assessment [ 5 ], blood sampling and diagnosis [ 9 ], dental health [ 8 ], COVID-19 infections [ 7 ], and prenatal diagnosis [ 3 ]. Two studies also address how remote assessment using online surveys can be implemented and used [ 2 , 6 ], and one study review health inequalities in real-time remote outpatient consultations [ 4 ].…”

“…This is also demonstrated by the study by Sacristán-Galisteo and colleagues [ 6 ] who demonstrate that the web-based Spanish Post-COVID-19 Functional Status (PCFS) scale provided substantial test-retest reliability as compared to the paper-based version. The study by Sosenko and Bramley [ 2 ] similarly shows how methods for collection of survey data can be moved from a laboratory-based to a remote smartphone-based approach. The study demonstrates how the Respondent Driven Sampling (RDS) survey method can be implemented using smartphone technology while mitigating the possibilities for fraud, which comes when human verification in the clinic is absent in remote assessment.…”

“…A clear benefit to remote assessment is a better recruitment process. Remote assessment (i) allows the recruitment of large and diverse samples of participants in terms of age, gender, origin, culture and social status [ 2 , 5 ], (ii) offers tremendous potential to engage representative cohorts, scale biomedical research, (iii) promotes accessibility by reducing barriers common in traditional trial design [ 7 ], and (iv) may help reach and drive uptake in under-represented participant groups [ 4 ] or groups that are “hard-to-reach” [ 2 ]. Moreover, some patient groups—like young university students—who are ‘digital natives’ may even prefer online platforms [ 1 ].…”

“…Not surprisingly given the timing and the wording of the call for papers, many of the papers address the COVID-19 lockdown and discuss how remote assessment methods can be used during a pandemic where people are more or less isolated and physical presence in clinics and between study participants needs to be minimized [ 1 , 2 , 4 , 6 , 7 , 9 ]. As argued by Sacristán-Galisteo and colleagues [ 6 ], the COVID-19 pandemic has led to an unprecedented situation in which there has been a major push to implement telemedicine consultations, emphasizing the need for remote assessment tools, which offers the possibility to assess patients’ functional status without needing outpatient visits.…”