This article offers reflection on the validity of relational data such as used in social network analysis. Ongoing research on the transformation of the support network of caregivers of persons with an Alzheimer-type disease provides the data to fuel the debate on the validity of participant report. More specifically, we sought to understand the factors that might influence the description of the support network by persons involved in caregiving. The issue warrants special attention, given that social relations--in their form and their content--constitute the raw material of network analysis. We propose that how persons describe their social network corresponds to a subjective process that rests, in part, on their representation of their cultural and social universe.