I am very disappointed that trainers / instructors and students can not see what questions were incorrect. 2 things....
1. Instructors need to know generally what types of questions are being missed and why for process improvement and to validate student understanding.
a.  It gives the instructor ability to improve instruction technique, material presentation which helps reinforce important criteria.
b.  Instructors should provide IPC feedback on incorrect, ambiguous, and misleading test questions that confuse everyone! Frequently students get the same wrong questions, which then instructors and IPC can do trend analysis, test/curriculum efficacy, and instructor awareness.
2. Students need to know what questions they got wrong.  Students/ companies pay to receive training and instruction! It is not all about the certification.  Instructors are there to help them learn and  understand.
a. Students not will be able properly navigate documents if they are getting questions wrong and don't know why.
b. Also, students will not able to properly apply requirements if they do not understand criteria.  

In closing, IPC and trainers are doing their students and EMS / CM companies (all of which are our clients) a disservice by not properly training students; they will not be able to learn from their mistakes if they don't know what is wrong. We as trainers are obligated to help students learn and understand the information we are presenting....especially when they get test answers wrong! If you agree please post or send a note to IPC.
Thank you