One of my ongoing complaints is the lack of clarity in Modern Astrology. Nowhere is this more manifest in the technique that is referred to as the 12-letter alphabet. This is a thoroughly modern concept which was first introduced in 1973 in Finding the Person in the Horoscope by Zipporah Dobyns, who is widely credited with having invented it. (Note that Dobyns held a Ph.D. in psychology, and like most modern astrologers, focused on astrology as psychology, not as a predictive art.) This seems to have been an attempt to simplify astrological associations so that it would be easier for beginning students to learn (which is a problem in and of itself; after all, it's not an "easy" subject, it shouldn't be "easy" to learn).
The idea is that the first sign of the zodiac, Aries, is like the first house in the chart, and they are both like the planet that rules Aries, Mars. So Aries=1st House=Mars. I'm not sure where to begin with how wrong this is historically, and how this confuses and conflates based upon near-complete misunderstandings of a number of concepts. First of all, the planet are not the signs of the zodiac. Planets were/are considered divine energies that resonate/associate with all things sub-lunary (on Earth); the physical planets themselves are "merely" a physical resonation/representation of the divine energy of that particular planetary deity/angel/etc. So it's not the rock that we call "Mars" that "causes" martial things on Earth; it's the energy behind it that resonates to the planet and all things on Earth that we associate with Mars (aggression, war, drought, assertiveness, red, iron, etc.). The Signs have relationships with the planets. Each planet is essentially in charge of the affairs of one or more signs, or portions of signs. This relationship is complex, and we determine the details of it in the essential dignities' scheme. Aside from each planet ruling one or two signs, each of the the planets is considered to be exalted in one of the signs; each one has a special relationship with the triplicites (e.g., the fiery triplicity is all of the fire signs: Aries, Leo, Sagittarius). And so forth. Dobyns cavalierly discarded Exaltations based not upon an understanding of the principle of Exaltation, but rather based upon her own inadequate interpretations of how each planet acts in its sign of exaltation.
While it's true that each sign of the zodiac moderates or filters the energy of the planet, the sign rulerships and exaltations were not originally assigned based upon any particular planet being like any particular sign. There are similar energies between some of them, but a planet is the ruler of a sign because it is the most appropriate planet to dispose of the affairs of that sign. So Mars rules Aries, not specifically because Mars is like Aries (though it is, in fact, somewhat similar); but rather because Mars is the planet that takes care of the affairs of Aries in a chart, regardless of whether Mars happens to be in Aries at the moment.
Houses are indicators of different areas of life. For example, if a chart has Mars in the first house, then Mars will directly influence the physical body, the health and happiness of the native. If Mars is in the second house, he will directly influence the native's money and movable wealth, but will not influence health and happiness, unless he is otherwise linked to the first house. This ability to discern and distinguish that one thing is not another is critical in delineating a chart, and especially in attempting prediction based upon it. And getting the connections and relationships correct is paramount.
Yet somehow, the idea quickly developed that there is a "natural" chart. That is, that the first house has an "underlying" Aries energy always, regardless of what sign actually appears on the first house cusp in any particular chart. Let's see how this would work.
Imagine that Gemini is rising (and therefore on the cusp of the first house), and that Mercury, its ruler, is in the third house in Leo. The Sun, which rules Leo, is in the eighth house in Capricorn.
So in this chart the:
1st house = Gemini = Aries (as the underlying, "natural" energy of that house) = Mars (as the ruler of Aries) = Mercury (ruler of Gemini) = 3rd house (where Mercury happens to be in this chart) = Leo (on the cusp of 3rd) = Sun (ruler of Leo) = Capricorn (where the Sun is in this chart) = 8th house (Capricorn is on the cusp) = Saturn (ruler of Capricorn) etc...Without even starting to delineate the meanings of these planets, signs, and houses, one can see how bloody confusing it all is. When one gets to the point where anything in the chart is equal to nearly everything else in the chart, it's impossible to extract any real meaning from it. This has also led to the fallacious re-assigning of certain house meanings. For example, traditionally, the fourth house is associated with the Father of the native. However, since Cancer is the fourth sign of the zodiac, and is feminine and associated with mothering or nurturing, modern astrologers have simply switched the meaning. After 1900 years of tradition, with no empirical or observational bases upon which to do so. Other changes that are a result of this in the last few decades are the negative associations of the 8th and 12th houses, being associated with Scorpio and Pisces, respectively. Virgo, the 6th sign, is now somehow about "healing" and "service," since the 6th house is associated with potential illness and servants. Venus is now supposedly connected to money, since she rules Taurus, which is the second sign, and the second house is about money (the traditional ruler of money is Jupiter and the 2nd house). There are other mis-associations, but the reader should have the idea by now that the current state of modern interpretation is at best confused. This is one of the reasons (but only one) why we find that modern astrologers don't even attempt to predict; the bottom line is that if one's associations and relationships are all wrong, it will be impossible to achieve clarity and any sort of real-world accuracy.
Dr. Dobyns uses the term "alphabet soup" in her own book, however, detractors of this method have turned it back onto the technique in the attempt to show that when everything equals everything, then the result is really nothing.