Includes bibliographical references (leaves 206-239) / The primary aim of the study was to develop a psychosocial assessment tool for determining willingness to participate in child-centred safety promotion interventions, specifically in a low-income community in South Africa. The secondary aim was to determine the factors associated with willingness to participate. The study employed a mixed methods approach to develop the measure, and included content validation, item writing and initial validation processes. Nominal Group Technique discussions were conducted with various role-players in the relevant communities to inform the development of the instrument, while participatory methodologies were utilised to conceptualise the instrument in relation to psycho-social factors associated with intervention participation, with these categorised according to core dimensions. A Delphi method utilising an expert panel reviewed items for relevance, difficulty and ambiguity, with items subsequently amended or removed. Item selection procedures were conducted on the English version of the instrument and these results were applied to the Afrikaans version. A pilot study was conducted as part of the initial validation in order to test the items and format the questionnaire. The instrument was then administered to Afrikaans speaking individuals in a community in the Western Cape. Iterative exploratory factor analysis was conducted at both the item and scale levels to select and reassign items and scales in order to determine the final composition of the questionnaire. The findings indicate that the instrument measures seven factors, namely incentives; priorities and community needs; perceived benefits; social approval; accessibility and values; altruistic capital; and community cohesion. These factors are explained in terms of the Process-Person-Context-Time model and the Theory of Planned Behaviour, considered within a participatory framework. The study findings indicate that the seven factors represent salient dimensions of the construct willingness to participate in interventions. The questionnaire and its subscales displayed acceptable to good reliability, with Cronbach’s α ranging from 0.55 to 0.80. Since willingness precedes actual participation, it is argued that insight into the factors that relate to willingness to participate provides an avenue for motivating actual participation. / Psychology / Ph. D. (Psychology)