What does it mean to reason well? One might argue that good reasoning means that the outcome of the reasoning process is correct: reaching the right belief. Alternatively, good reasoning might refer to the reasoning process itself: following the right epistemic procedures. In a preregistered study, we investigated children’s (4-9-year-olds) and adults’ judgments of reasoning in China and the US (N = 256). Participants of all age groups evaluated the outcome when the process was kept constant - they favored agents who reached correct over incorrect beliefs, and they evaluated the process when the outcome was kept constant - they preferred agents who formed their beliefs using valid over invalid procedures. Developmental changes emerged when we pitted outcome against process: young children weighed outcome more heavily than process; older children and adults showed the reverse preference. This pattern was constant across the two cultural contexts, with the switch from outcome to process happening earlier in development in China. These results suggest that children initially value what someone believes, but, with development, come to increasingly value how beliefs are formed.