The rise of evaluation and data in education and education policy is a trend manifesting across a wide variety of policy contexts, holding in its grip national and global policies, with impacts that reach the level of individual children, teachers, and their subjectivities. Earlier research has mainly focused on the phenomenon in neoliberal contexts. This article presents a case study of Finnish early childhood education and care (ECEC) policy discourse built on a tradition of social democratic political rationality and egalitarian values. By utilizing Evert Vedung's metaphor of evaluation waves, we examine how the evaluation trend has influenced the Finnish ECEC policy, which has traditionally been skeptical toward the assessment of individual children's learning and skills and the production and use of data for accountability purposes. In the genealogical reading of ECEC curricula and policy documents from 2002-2021 as data, we identify three discursive practices -- "partnership, pedagogization, and evidence wave" -- that have socio-historically contributed to the formation of the present conception of evaluation in the Finnish ECEC policy discourse. Our genealogical reading also reveals a movement toward international trends -- evaluating the individual child's skills -- especially through the evidence wave.