4.1. Descriptive aspects
4.1.1. Factor analysis and Internal Consistency of the Neo-FFI and the PCB
In this sample, we have checked the internal structure of the Neo-FFI using the Principal Components Analysis (PCA). Based on the results of the Screetest (Cattell, 1966), and on the results of previous research, that has shown that five factors were always found, we decided to take five factors into our research. After Varimax rotation, these factors are clearly interpretable. We have found the same factors as these what are proposed in the Five Factors of personality Model of Costa & McCrae (1978, 1992, 1995). The Eigenvalues of the five rotated factors are for Neuroticism, Extraversion, Agreeableness, Conscientiousness and Openness to Experience respectively 5.79; 4.78; 3.72; 4.31 and 3.68. The proportion of explained variation is for these factors respectively 10%; 8%; 6%; 7% and 6%, which results in a total explained variation of 37%.
The Internal consistency (Cronbach‘s Alpha) of the five factors of personality is .87, .82, .72, .78 and .70 for respectively Neuroticism, Extraversion, Agreeableness, Conscientiousness and Openness to Experience. The Internal consistency of Openness to Experience can be increased to .74 when the Openness to Experience -items 02, 06 and 08 are skipped from the questionnaire. Moreover, when we’ve done an extra factor analysis on the items of the Openness to Experience–factor, it seems to us we can divide these items into two groups. This new-made scale has an Alpha of Cronbach of .74, which is a higher one than the original one (Alpha-coefficient = .70). We’ve decided not to use this new-made scale, because there is no