Bias in Astrotheme data?

One interesting study I did today was to see if there was bias in the relationship between Sun and Ascendant signs in Astrotheme data. Most astrology sites that do natal interpretations base data with unknown birth times on a midday birth, which means the Sun will be conjunct the Midheaven. Of course, in most cases where the birth time is unknown it will not have occurred around noon. In order to test whether there is this sort of bias even among “known” (which includes doubtfully known) birth times, I have had a look on Astrotheme at a list of people born with Moon and Ascendant in the same sign and tabulated how the full list compares to the Sun sign by aspect:

• Zero signs: conjunction, or a “triple” with Sun, Moon and Ascendant in same sign
  • Only 136 celebrities out of 18,520 (0.73 percent) were born with Sun, Moon and Ascendant in same sign
  • This equates to one in 136, not significantly different from the predicted one in 144
  • Another 1,413 celebrities (7,629 percent) were born with the Moon and Ascendant in the same sign but the Sun in another sign
    • It is notable how often this occurs among people near me, including myself: 5 of 56 people close to me or my brother have Moon and Ascendant in same sign, but there are no “triples”.
• Positive one sign: the Sun sign is one sign after the Moon/Ascendant sign; e.g. ☉in ♌ with ☽ and Ascendant in ♋.
• Positive two signs: the Sun sign is two signs after the Moon/Ascendant sign; e.g. ☉ in ♐ with ☽ and Ascendant in ♎.
• Positive three signs: the Sun sign is three signs after the Moon/Ascendant sign; e.g. ☉ in ♌ with ☽ and Ascendant in ♉.
• Positive four signs: the Sun sign is four signs after the Moon/Ascendant sign; e.g. ☉ in ♍ with ☽ and Ascendant in ♉.
• Positive five signs: the Sun sign is five signs after the Moon/Ascendant sign: e.g. ☉ in ♏ with ☽ and Ascendant in ♊ (as in my own chart)
• Six signs (positive or negative makes no difference): the Sun sign is opposite the Moon/Ascendant sign: e.g. ☉ in ♈ with ☽ and Ascendant in ♎.
• Negative five signs: the Sun sign is five signs before the Moon/Ascendant sign: e.g. ☉ in ♓ with ☽ and Ascendant in ♌.
• Negative four signs: the Sun sign is four signs before the Moon/Ascendant sign: e.g. ☉ in ♑ with ☽ and Ascendant in ♉.
• Negative three signs: the Sun sign is three signs before the Moon/Ascendant sign: e.g. ☉ in ♐ with ☽ and Ascendant in ♓.
• Negative two signs: the Sun sign is two signs before the Moon/Ascendant sign: e.g. ☉ in ♍ with ☽ and Ascendant in ♏.
• Negative one sign: the Sun sign is one sign before the Moon/Ascendant sign: e.g.☉ in ♌ with ☽ and Ascendant in ♍.

Tabulating all the possible combinations as explained lengthily above gives the following result:

What one sees is that there is:

1. a very distinct peak three signs before the Moon/Ascendant sign
2. a less distinct though significant trough five signs before the Moon/Ascendant sign

These suggest that, in spite of efforts to exclude those with unknown birth times, astrology databases still have some problems of bias.

One way possibly of dealing with this problem would be to make sure that birth times are not taken as noon when unknown, and only to take a noon birthtime from a birth certificate, biography or correspondence. Whether this will help correct the bias from the simple test above is a fascinating question.