The volunteer participation paradox: Ethical tensions between self-selection and targeted sampling

The voluntary nature of research participation is a cornerstone of ethical practices in studies involving human participants. However, when individuals voluntarily respond to participant calls or are selected through convenient methods, they often share traits like proximity or willingness—possibly leading to data skewed by similar attitudes. Conversely, methods aimed at diversity and inclusion, such as snowballing or maximum variation sampling, might inadvertently compromise the voluntary nature of participation. This tension, which I term the volunteer participation paradox , presents researchers with a methodological dilemma. That is, when participation is entirely voluntary, research may face limitations due to potentially unbalanced data. In contrast, when researchers employ targeted sampling strategies to gather broad-ranging data, the authenticity of voluntary participation may be influenced by factors such as social obligation or researcher relationships. This article explores manifestations of this methodological tension and puts forward guidance for navigating the complex ethical terrain in research methodology.