And no, the ape/mammal comparison is inapplicable. That is not how these systems are classified. And I have not misunderstood my textbook. Here is how that book - again, it's Geography of Elections by Taylor and Johnston - classifies the systems it discusses.
1. The Plurality System
(i) The plurality system in single-member constituencies
(ii) Multi-member plurality sytems
(iii) Weighted plurality systems
2. Preferential systems
(i) Single-member preferential systems
(a) The alternative vote [i.e. IRV, which did not yet have that name]
(b) The double-ballot
(ii) Multi-member preferential systems
(a) The single transferable vote
3. List systems
(i) The simultaneous list
(ii) The local list
(iii) The party list
4. Mixed systems [which it doesn't enumerate in a list]
In the description of STV, page 59 of the Penguin edition, it says, "If, as with our hypothetical example, no candidate exceeds the quota of 651 and there are still seats to be filled, the procedure used in the alternative vote [that is, IRV] is operated."
So it acknowledges the relationship between the two, but you see that it depicts STV as borrowing the procedure for IRV - which, in fact, it does not always need to do in actual cases - not as IRV being a special case of STV.
You can look at them that way if you want, but it is not inaccurate to say that they are different systems and that a single-winner election using it should say it is using IRV, not STV.
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timeasmymeasure
no subject
Date: 2007-01-24 03:54 pm (UTC)1. The Plurality System
(i) The plurality system in single-member constituencies
(ii) Multi-member plurality sytems
(iii) Weighted plurality systems
2. Preferential systems
(i) Single-member preferential systems
(a) The alternative vote [i.e. IRV, which did not yet have that name]
(b) The double-ballot
(ii) Multi-member preferential systems
(a) The single transferable vote
3. List systems
(i) The simultaneous list
(ii) The local list
(iii) The party list
4. Mixed systems [which it doesn't enumerate in a list]
In the description of STV, page 59 of the Penguin edition, it says, "If, as with our hypothetical example, no candidate exceeds the quota of 651 and there are still seats to be filled, the procedure used in the alternative vote [that is, IRV] is operated."
So it acknowledges the relationship between the two, but you see that it depicts STV as borrowing the procedure for IRV - which, in fact, it does not always need to do in actual cases - not as IRV being a special case of STV.
You can look at them that way if you want, but it is not inaccurate to say that they are different systems and that a single-winner election using it should say it is using IRV, not STV.