Formative assessment and effective use of data to support student learning are key components of practice in early childhood (EC) centres. Although Trinidad and Tobago has developed an impressive EC care system, to decrease the achievement gap which international studies have shown to be significant in core subjects, educational planners must ensure that teachers make better use of data. This study explored data use practice in eight geographically diverse EC centres. Using maximum variation sampling, data were collected from focus group teacher interviews, observation and document analysis. Thematic analysis and constant comparison were used to identify differences across sites and to generate theory on practice. The theory identifies data use practice in an emerging Caribbean society lacking a robust data culture and with limited professional development opportunities. Implications for policy, professionals development and system reform of the EC sector in Trinidad and Tobago are included.