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The influence of birth order on personality remains unconfirmed. In fact, there are too many complex variables modifiers which influence it; therefore, the measurement of birth order’s impact on personality and deflection caused by it on character’s examination results, are impossible. Main distorters to the outcome are such factors as: family size, family’s financial and social status, gender structure, upbringing methods and its environment. For example, bigger families statistically perform lower financial status that often entails lower social status, both of which may restrict educational possibilities. Also, gender of firstborns influences later siblings, for this, as well as parenting methods and environment, does change the responsibility, trust and general treatment style bestowed from adults to children.
The influence of birth order on personality
Moreover, some initially associated qualities according to birth order were proven baseless and even misinforming. The only one reliable research were narrowed to examine birth order’s influence on siblings’ IQ index exclusively. It had been carried out in Switzerland on a group of 6,3 thousand 19-years-old men and has shown, that, on one hand, every next child has IQ lower of 1 point. On the other hand however, associated scientific research has proven that IQ index is over ten times less important than conscientiousness and openness to new experience, concerning attitude represented in adulthood. That is, IQ level were accredited influence on one’s personality in less than 1%. In conclusion, according to the one comprehensive digest of studies which were conducted on that issue during the years 1946-1980, modern scientists described them as inconclusive, unclear, misinforming and “generally a waste of time”. Henceforth this question was put aside.
 Ernst, C. & Angst, J. (1983). Birth order: Its influence on personality. Springer.