When designing an electoral system, it is best to start with a list of criteria that sum up what you want to achieve, what you want to avoid and, in a broad sense, what you want your parliament and government to look like. The criteria given in Ensuring a Representative Parliament to Promoting a Parliamentary Opposition cover most areas, but the list is not exhaustive and the reader may add a host of equally valid items. It is also true that some of the criteria outlined overlap and may appear contradictory. This is because they often are, and it is the nature of institutional design that trade-offs have to be made between a number of competing desires and objectives.

For example, one may want to provide the opportunity for independent candidates to be elected, and at the same time to encourage the growth of strong political parties. Or the electoral system designer may think it wise to craft a system that gives voters a wide degree of choice between candidates and parties, but this may make for a complicated ballot paper that causes difficulties for less-educated voters. The trick in choosing - or reforming - an electoral system is to prioritize which criteria are most important and then assess which electoral system, or combination of systems, best maximizes these objectives.