This article shows the difficulties encountered by quantitative research when investigating the financial and material support given to young adults by the family. It is based on a secondary analysis of empirical materials from an exploratory survey which aimed at testing, before carrying out a larger statistical survey, a tool for counting amounts donated by parents to their children. The improvement of an accounting approach for measuring parental financial support to young adults –observed more widely in the evolutions of public statistics– does not paradoxically reduce some of the blind spots of family support. Indeed, respondents show various forms of resistance to this directive mode of questioning the parental support. However, behind the apparent incommensurability, parents do evaluate their support, but not necessarily using a simple equation, in which the total financial support would exclusively depend on the household resources. The perceived needs of the child, their potential merits, the characteristics of the siblings or the help received by the parents in their own youth are all factors that can impact the parental support. By analyzing all these criteria, this article thus contributes to highlighting the intergenerational standards of solidarity that guide parents’ calculation methods. It ultimately questions protocols for measuring aid in statistical surveys.