Promising findings from controlled research studies often fail to be transferred to and implemented in schools successfully. This problem is particularly apparent when considering implementation of evidence-based practices related to complex systems such as response to intervention (RTI) and other multitiered intervention frameworks in mathematics. This article addresses the challenges schools face when implementing intensive intervention in mathematics with a data-based individualization (DBI) framework. Preliminary findings from the first year of a formative evaluation study that addressed school-based implementation of DBI include (a) factors that impacted readiness for DBI, (b) the application of DBI at school sites, and (c) the importance of ongoing coaching and consultation. We then discuss practical implications for schools and districts when planning for intensive intervention in mathematics.