Open-Source Psychometrics Project
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Firstborn Personality Scale

This is an interactive personality test that measures the differences between firstborn and later born siblings.


The effect of birth order on personality has been speculated about since about since the beginning of psychology as a science. The general idea is that children at different positions in the birth order would receive different treatment from their parents, or would have a different experince within the hierarchy of siblings. This has been supposed to lead to systematic differences in personality by birth order. Many common claims about this are wrong or exaggerated, birth order has only very small and very narrow effects of human personality and the difference is mostly between firstborns and later borns (Rohrer et. al., 2015).

The Firstborn Personality Scale was developed by selecting items that differentiated between firstborns and later borns to make a measure that is as predictive of birth order as possible. A wide ranging set of 375 questions were tested and the best 25 were kept. It produces differences between first and later borns nearly twice as large as any other self report scale, though still small. Read more about its development here.

Test Instructions

The test has 25 statements of opinion that you must rate on a five point scale of how much you agree with each. It should take most people 3-5 minutes to complete.


This test is provided for educational and entertainment use only. It should not be used as psychological advice of any kind and comes without any guarantee of accuracy or fitness for any particular purpose. Also, your responses may be recorded and anonymously used for research or otherwise distributed.

  • Rohrer, Julia M., Boris Egloff, and Stefan C. Schmukle. "Examining the effects of birth order on personality." Proceedings of the National Academy of Sciences 112.46 (2015): 14224-14229.
  • "Development of the Firstborn Personality Scale." <>

ℹ️   Published: 18 July 2019 (Updated: 1 May 2023)

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