Much (perhaps too much) has been posted online concerning what I
shall refer to as "opinion taxonomy," or perhaps more ominously
"ideology taxonomy" or "agenda taxonomy." I shall start here
with a brief summary:

* Left vs. right

This is the most familiar, and probably also the most derided for
oversimplification. I happen to endorse it, partially for its
simplicity, but mostly for its solid consistency with life as I have
observed it so far. It seems that in every context there are insiders
and outsiders, overlords and underdogs, winning and losing track
records. It also seems that every status quo (statist or
otherwise) comes with its own tamper-proofing mechanisms designed to
protect the interests of insiders, overlords and winners from
outsiders, underdogs and losers.

* High-dimensional euclidean space

The most famous example is the biaxial Nolan Chart. Another is the
triaxial Pournelle Chart. A somewhat long-winded discussion of the
concept is found in the Wikipedia article "Political spectrum:"


* Chromatic factionalism

I first came across this on a European wiki (or tiki?) but have since
failed to "re-locate" it. This offers some flexibilities in that one
can mix and match factions, as in my own self identification with both
the red (egalitarian) and black (antiauthoritarian) factions. I have
proposed a "model agnostic" (though computationally intensive)
approach to factionalism in my blurt titled "Chromatic Content Coding"
at halfbakery.com:

http://www.halfbakery.com/idea/Chromatic_20Content_20Coding#1141759425

Halfbakery seems to have shuffled its namespace schema (or "dongling
schema" as I call them), so the above URL might not work as is.

* Percentage-based schemata

This is the preferred approach of many American special interest
groups (SIG's). It consists of rating policymakers (at least
legislative branch policymakers) on a scale of 0-100%. The percentage
often represents simply the percentage of times a given politician
voted the same way a given SIG would, given a seat in the legislature.
Sometimes it is perhaps a weighted average. Not all SIG's are
transparent about precisely which bills are included for "analysis."
This approach to taxonomy can lead to absurdities such as David Brooks
(7 Jul 2006 "News Hour," PBS) classifying Joe Lieberman as some kind
of überliberal thanks to a 0% rating by Christian Coalition.