The MMM electoral system adds an element of proportionality to Single Winner by the addition of list seats .
However , the ratio of FPTP seats to PR seats , the quantify of overhang seats , and the threshold needed to acquire PR seats are contributing factors as to why MMP produces semi-proportional results.  MMM adds an element of proportionality to Single Winner by the addition of list seats , but distributes only the list seats proportionately without compensating for disproportions in the distribution of single-winner seats.
Proportional representation