The PROsetta Stone® project represents a major step towards clarifying the relationships between instruments that measure similar constructs.
By applying three different linking methods, the PROsetta Stone® methodology places two instruments on the same metric, allowing the creation of a cross-walk table. This cross-walk table matches each possible score on a "legacy" instrument to a T-score of the comparable PROMIS instrument. (The PROMIS T-score has a mean of 50 and a standard deviation of 10, and is centered on the US general population.)
In order to link two instruments, the PROsetta Stone® project analyzed data from single-case design studies, meaning that all items from both instruments were administered to the same sample.
Data were obtained from existing datasets in PROMIS, Neuro-QoL, and NIH Toolbox studies; in addition, three waves of data were also collected specifically for the purpose of linking.
The samples included both adult and pediatric data; instruments were linked in major health outcome domains, including depression, anxiety, fatigue, pain, sleep disturbance, and physical functioning.
To learn more about the methodology used in the PROsetta Stone®, refer to the Methodology Report.