How can AMS lead to wasted votes?

The correct answer highlights how the Additional Member System (AMS) can lead to wasted votes through the specific design of electoral regions. In AMS, voters cast two votes: one for a candidate in their constituency and another for a party list. If the boundaries of the constituencies are drawn in such a way that they disproportionately favor certain parties, it can result in many voters' preferences not being reflected in the final outcome.

For example, if a particular party is very strong in a given area, it may win most of the constituencies, meaning that votes for other parties in that region do not contribute to any representation. This can lead to a scenario where a significant number of votes do not impact the overall election results, effectively becoming "wasted." This issue arises not from the principle of representation itself, but rather from the geographical and political decisions behind how the voting regions are structured. In contrast, an equitable representation or reduction of parties generally aims to minimize wasted votes, illustrating how the construction of electoral systems has profound implications on voter efficacy.