This is a free online version of the IPIP personality test measuring scales similar to that of the Revised NEO Personality Inventory, of which this website has no affiliation.
This test is based on the five factor model, the best accepted scientific theory of personality which describes individuals in terms of five fundamental traits. In addition to a standard big five personality test the NEO-PI-R model of personality includes six "facets" to each trait.
The Five Factor Model was developed by the study of adjectives where it was assumed that over time all important measures of personality would be encoded into language. The first researchers in this are gave study participants long lists of adjectives and told them to rate them on how much each applied then used a technique called factor analysis to try and boil down their answers to underlying independent factors.
The NEO PI-R is one of the most widely used instruments in psychology but it is copyrighted and so can not be offered online for free. This test uses the public domain scales from the International Personality Item Pool which have been shown to be mostly identical.
This test will not reveal any secret information about you, nor will it be able to prescribe proper behavior for you. It will reveal however in a very scientifically robust manner how the structure of your personality compares to others.
This test is quite lengthy. It consists of three hundred items that must be rated on a five point scale of (1) Disagree (2) slightly disagree (3) neither agree nor disagree (4) slightly agree and (5) agree and will take between fifteen and forty minutes to complete.
This test is part of a research project and so all information you enter from this point on will be collected and stored for potential use, it may also be shared at will. None of the information could reasonably by used to identify you, however, and this website does not know your identity, so your participation should be anonymous.
This test is currently disabled while being improved.