The motivation for using this method is the requirement to understand which services are in highest demand (or valued most) in a particular context (or the ones that are socially perceived as the most vulnerable). This approach could be helpful to: (i) demonstrate the social importance of ecosystem services, (ii) set priorities within management strategies (e.g. working first on those services characterized as highly vulnerable but highly demanded) within the context of the ecological status of other ecosystem services (declining, stable or improving); (iii) to understand the multiple needs of different stakeholders and, in doing so, anticipate potential social conflicts derived from policy decisions affecting different ecosystem services.
Preference assessment is a direct and quantitative consultative method for analyzing perceptions, knowledge and associated values of ecosystem service demand or use (or even social motivations for maintaining the service) without using economic metrics. It can also be used to understand which ecosystem services are perceived as the most vulnerable, or which make the greatest contribution to human wellbeing. Data is collected through surveys using a consultative approach. Preference assessment is a useful approach for identifying relevant services from different stakeholder perspectives with diverging interest or needs. Its application can help to uncover differences and similarities in preferences between different social groups in terms of ecosystem service demands.