Scientific Foundations and Psychometric Validity Report

Purpose

This report summarises the development process of the CharacterIX Personality Inventory, its psychometric validity and reliability results, and the academic applications carried out in areas such as leadership, educational management, sales and career counselling.

The inventory aims to validate the nine-type personality typology of the Enneagram within a scientific framework using modern measurement methods.

Method

2018 – CharacterIX GB-TR Scientific Study

Yılmaz, O., Yıldırım, A. and Yücedağ, D. (2018). Assessment of Personality from a New Perspective: Characterix Personality Types Inventory. International Journal of Scientific Research and Management, 6(3), EL-2018-103–116. DOI: 10.18535/ijsrm/v6i3.el02

Starting from a pool of 174 items, the inventory was developed through expert review and a pilot application; its final version consists of 72 items, eight for each of the nine factors. Items are answered on a four-point Likert-type scale (Strongly agree, Partly agree, No opinion, Disagree).

🔬 Scientific Evaluation and Results

Data from 21,140 participants aged 17–38 from various provinces of Turkey were randomly split into two groups: Principal Component Analysis (PCA) was applied to the first group and Confirmatory Factor Analysis (CFA) to the second (n = 10,570). The results show that the nine-factor structure of the CharacterIX Personality Inventory supports the theoretically proposed Enneagram-based personality model.

Principal Component Analysis: KMO = .942; total variance explained by the nine factors 49.55%.

Confirmatory Factor Analysis fit indices: CFI = .92, NNFI = .91, RMSEA = .074, SRMR = .082, GFI = .77, AGFI = .79. The CFI, NNFI and RMSEA values indicate an acceptable model fit, while the GFI and AGFI values fall below the recommended thresholds. The researchers attributed this to the complexity of the model and the structure of the sample.

Reliability: Cronbach’s alpha values by factor range from .727 to .879, and the overall reliability coefficient of the scale is α = .877. These results support the following scientific conclusions:

The scale shows high internal consistency in measuring personality traits; that is, the items in each factor measure the same psychological construct.

Alpha coefficients above .70 show that the reliability of the scale is above acceptable limits (Kaplan & Saccuzzo, 1989; Özgüven, 2007).

The confirmatory factor analysis findings show that the items represent their respective factors, supporting the construct validity of the scale.

The size of the sample (n = 21,140) shows that the findings are statistically robust for the Turkish sample aged 17–38.

In conclusion, the CharacterIX Personality Inventory is considered a valid and reliable psychometric instrument for measuring the nine personality types.

The high internal consistency of the scale provides strong evidence for analysing individuals’ personality profiles on a scientific basis and using them in counselling processes.

2018 – Paper at the 26th National Management and Organisation Congress

Acar, P., Yıldırım, A. and Yücedağ, D. (2018). Stratejik İnsan Kaynaklarının Dönüşümü: Enneagram Tipolojisi Bağlamında Liderlik Gelişimi [The Transformation of Strategic Human Resources: Leadership Development in the Context of the Enneagram Typology]. Proceedings of the 26th National Management and Organisation Congress, Karadeniz Technical University, pp. 823–831.

The inventory results of 28,484 Generation Z students at private and public universities across Turkey were analysed to assess leadership tendencies. In this sample, the reliability coefficient of the scale was α = .875 and the KMO value was .942. The findings were interpreted within the framework of the “Leadership Development Wheel” model.

2019 – School Administrators Thesis

Şirin, S. G. (2019). Enneagram Metodolojisi Tekniğine Göre Okul Yöneticilerinin Mizaç Dağılımının Karşılaştırmalı Olarak İncelenmesi [A Comparative Study of the Temperament Distribution of School Administrators According to the Enneagram Methodology]. Master’s thesis, İstanbul Okan University.

The inventory results of 1,111 school administrators across Turkey were evaluated to examine the distribution of dominant types among administrators.

2019 – Individual Differences in the Sales Process Thesis

Kurt, A. (2019). Kişisel Satış Sürecinde Bireysel Farklılıklar: Enneagram Tipolojisi Üzerine Bir Araştırma [Individual Differences in the Personal Selling Process: A Study on the Enneagram Typology]. Master’s thesis, Maltepe University.

The personality types and demographic characteristics of 95 personal sales staff in the telecommunications sector in Istanbul were examined in relation to sales performance.

2023 – Public Relations Doctoral Thesis

Özmansur, K. (2023). Halkla İlişkiler Mesleğinin Seçimine Yönelik Kişisel ve Mesleki Eğilimler: Halkla İlişkiler Bölümü Üniversite Öğrencileri Üzerine Bir Araştırma [Personal and Professional Tendencies in Choosing the Public Relations Profession: A Study on Public Relations University Students]. Doctoral thesis, Istanbul University.

The relationship between Enneagram types, career choices and perceptions of practitioner roles was analysed among 397 public relations students.

Areas of Application

Leadership (2018)

Type 2 (Helper) was found to be the most common type in the Generation Z sample. A distinctive leadership style was defined for each type, and the results demonstrated applicability in leadership development and human resources management.

Educational Management (2019)

Type 2 was again found to be the most common type among school principals. The low proportions of Type 3 and Type 8 indicated that humane leadership skills such as empathy, fairness and cooperation stand out in school administration.

Sales (2019)

Personality types and demographic characteristics of personal sales staff were examined together with sales performance. The study shows that the inventory can be used to understand individual differences in sales teams and to plan the development of sales staff.

Career Choice (2023)

Significant differences were found between personality traits and preferred professional roles among public relations students.

Type 3 students leaned more towards manager/strategist roles, while Type 9 students leaned towards communication/coordination roles.

Scope and Limitations

The psychometric validity study was conducted on the 72-item form with participants aged 17–38. The student (ages 11–18) and blue-collar forms were prepared by adapting the items of this form to the respective groups; no separate psychometric study exists for these forms.

The 136 potential-competency analysis presented in the reports is a model output derived from the directly measured nine-factor structure.

The 2019 and 2023 theses are independent application studies carried out by researchers outside CharacterIX, using the inventory with the organisation’s permission.

Conclusion

The CharacterIX Personality Inventory is a psychometrically validated, reliable and valid measurement instrument.

Research shows that the inventory can be used not only for personal development but also in leadership development, educational management, sales, human resources and career counselling.

📚 Sources and Documents

This report is based on the academic studies listed below. The full content and data can be accessed from the PDF documents available on this page (the theses and congress paper are in Turkish):