
Party-list proportional representation system is adopted in elections in the geographical constituencies. Though such system has been used numerous places, the Hong Kong version has got a number of defects which the government refuses to fix.
First, it employs the Hare quota instead of the Droop quota in determining the first few seats of the constituency. Under the largest remainder method, the last few seats in the constituency can be won with much lower percentage of votes. This encourages parties to split their lists and radical individuals may have a higher chance to get into the Legco. This is evident in the number of lists relative to number of seats in each constituency. For example, 13 lists, with a total of 30 candidates, are competing for 5 seats in the West Kowloon constituency.
Secondly, the system in Hong Kong does not allow voter to express their order of preference for parties. For example, it is highly possible that people who votes for the Civic Party may want to transfer their votes to the Democratic Party if they know their votes would not get an additional candidate to be elected on the Civic Party list. Under the current system, the voters have to try their luck to distribute their votes appropriately so their order of preference can be properly expressed. With a bit of misfortune, the election results could turn against the voters' expectations, as in the 2004 election. The best way going forward is to switch to a Single Transferable Vote system, which allows the voters to state their order of preferences.
A detailed explanation of the problems of the voting system can be found here.