These plausible values are calculated by the complex item-response theory (IRT) model (see Baker 2001; Von Davier and Sinharay 2013) based on the assumption that each student only answers a random subset of questions and their true ability cannot be directly judged but only estimated from thei...
Written by experienced examiner Marwan Mikdadi, this Student Guide for Economics: -Identifies the key content you need to know with a concise summary of topics examined in the A-level specifications -Enables you to measure your understanding with exam tips and knowledge check questions, with answe...