Three parallel twin studies of early reading development were conducted in Australia, Colorado, and Scandinavia (Norway & Sweden). Investigators Brian Byrne, Richard Olson, and Stefan Samuelsson have committed to creating a unified data set suitable for cross-country comparisons. This study is known by a host of acronyms including:
- RDS: Reading Development Study
- ERDS: Early Reading Development Study
- LSERD: Longitudinal Study of Early Reading Development (thus the lizard)
Data from each assessment wave from each country is sent to a single location (currently IBG - Robin Corley) for creation of a unified assessment wave data set, e.g., IT (Initial Test) or F1 (Follow-Up 1). Selected variables from the individual waves are then combined into a working individual-level cross-assessment file, and a twin-pair (double-entered) cross-assessment file.
The files that are available for download are listed below. They represent SPSS Export (Portable) files that can be opened by either SPSS or SAS.
All ERDS collaborators have a responsibility to use the ERDS data responsibly, including restricting access to these files to those colleagues who have requested and received permission to work with the data. Please notify the site manager IMMEDIATELY if information is found in the files that directly identifies families (e.g., date of birth).