Read a brief description of CALDER's data by state.

CALDER's focus capitalizes on what is emerging as the richest new source of information about schools, teachers, and students in the United States—state administrative longitudinal databases.

Our focus on state and district administrative longitudinal databases has a number of advantages:

1. The state databases at the core of our work are census files. That is, they include all districts, schools, teachers, and students in the state. Census files do not confine us to a sample selected under informationally imperfect assumptions.
   
2. We have data from multiple states and we can, therefore, conduct replication studies. Analyses conducted in one state are confined to the data and measures available in that state, and interpretation of the findings is confined to the context conditions associated with that state. Replication in a different state, with perhaps different measures and with a different context, can provide important information on intermediary factors and the robustness of effects.
   
3. Our data extend into the past as well as the future. A key question in policy research is identifying the baseline from which to start assessing effects. Policy is rarely, if ever, written on a tabula rasa.
   
4. Our data allow us to distinguish patterns of student racial, social, and achievement segregation as well as teacher quality at the district, school, and even classroom levels.
   
5. CALDER's team is experienced with analyzing longitudinal data in education.