This question is worded a bit weirdly. I don't do this subject, but I'm guessing it is asking to evaluate how effective each head injury assessment is promoting safety. For example, a comprehensive pre and post incident procedure would ensure that the head injury is managed in a safe and effective way. My guess is:
1: Boxing (pre, post, incident report, medical review)
2: Horse racing (pre, post, medical review)
3: F1 racing (contains all but not as comprehensive as other sports)
4: Rugby (no pre-incident exposure)
5: Football (no penalty exists)
I would assume boxing is the best evaluation of safe participation because of the stringent measures (incident recording & official medical review) that are in place to ensure safety for the person participating in the sport.
Again, I don't do this subject and if it seems completely incorrect, don't use the information. But this subject sounds interesting. Are you studying in NSW? This subject isn't available in QLD. :/