Analysis of information sources in references of the Wikipedia article "Hindu astrology" in English language version.
Each planet is supposed to be the karaka or indicator of certain events in life
To optimise the chances of finding even remote relationships between date of birth and individual differences in personality and intelligence we further applied two different strategies. The first one was based on the common chronological concept of time (e.g. month of birth and season of birth). The second strategy was based on the (pseudo-scientific) concept of astrology (e.g. Sun Signs, The Elements, and astrological gender), as discussed in the book Astrology: Science or superstition? by Eysenck and Nias (1982).
Each planet is supposed to be the karaka or indicator of certain events in life