Relative Diagnostic Profile: A Subscore Reporting Framework

Subscore reporting under item response theory models has always been a challenge partly because the test length of each subdomain is limited for precisely locating individuals on multiple continua. Diagnostic classification models (DCMs), providing a pass/fail decision and associated probability of pass on each subdomain, are promising alternatives for subscore reporting. However, it may not be appropriate to provide those binary decisions or probabilities to examinees when (1) an overall score is provided with a pass/fail decision from standard-setting procedures or (2) absolute decisions or probabilities are not the purpose of providing subscores. To satisfy such score reporting scenarios, this article introduces the relative diagnostic profile (RDP), a framework using DCMs to score item responses but withholding absolute decisions and probabilities. In the RDP framework, a person's overall ability is a pie, where stronger subdomains are bigger slices. Beyond the within-individual information, this framework can also be used to compare a person's relative strengths to those of a chosen group of examinees.