Account for the rules in a measurement system? Shifts, wind, rules, etc. - all these things are applied equally to all boats on the race course by the very nature of "racing"...you don't need to normalize the results for them.

Portsmouth also uses the better sailor in the most substantiated (with overall handicap data) class in the event as the basis for the calculation - i.e. to determine what the potential of the boat was given those conditions. It takes most of the conditional issues out of the equation. The data also has to be consistent in order to be factored in and the numbers need to mostly make sense before the system uses them to change anything. For instance, if a Hobie 14 beats a Supercat 20 tall rig, or a boat rated 68.1 comes out with a rating that should be 130, the data is obviously skewed or inaccurate and isn't considered.

I'm not arguing that it's perfect (or even near perfect) - but to suggest that Portsmouth is flawed because of port/starboard rules or by the conditions on the course is not being truthful to the system.