This application allows you to transform BPRS, PANSS and CGI scores using equipercentile linking.
The PANSS measures positive and negative symptoms of schizophrenia. It contains 30 items rated from 1 to 7, resulting in a sum score ranging from 30 to 210.
The BPRS-18 measures psychiatric symptoms including depression, anxiety, hallucinations and unusual behavior. It contains 18 items rated from 1 to 7 (sum score: 18 to 126).
The CGI measures the severity of psychopathology on a score from 1 ("normal, not at all ill") to 7 ("among the most extremely ill patients").
The conversions provided in this application are based on the equipercentile linking approach employed by Leucht et al. (2005a; 2005b; 2006). In these studies, cross-walks were derived from individual participant data (IPD) of 13 antipsychotics trials in patients with acute schizophrenia (N=5970).
Equipercentile linking, the statistical approach employed to perform the conversion, acknowledges for the fact that scores of different rating scales are always burdened by some degree of measurement error, and therefore cannot be linked using conventional regression approaches. Instead, scores on different rating scales are matched based on their percentile rank. In the cited studies, a realization of the algorithm described by Kolen & Brennan (1995; Chap. 2) was used to achieve this.
The current application was developed using shiny. Conversions are performed with .