Translation and Validation of the German Version of the Ikigai-9

Abstract

Background: The Japanese concept of “ikigai” embodies the feeling of having a meaningful purpose in life. It is associated with several positive outcomes. This study aimed to translate and validate the German version of the Ikigai-9 scale (Ikigai-9-G)—and ikigai scores for certain groups of interest were presented. Methods: Data were taken from a quota sample of the German adult population aged 18 to 74 years (n = 5000; representative in terms of age, sex, and state). Data were collected in August/September 2023. The translation process was conducted in accordance with the existing guidelines. Reliability (Cronbach’s alpha; McDonald’s omega) was assessed. Moreover, we evaluated the structure’s soundness using confirmatory factor analysis for construct validity and examined concurrent validity by exploring pairwise correlations between the Ikigai-9-G with life satisfaction, happiness, health-related quality of life, depressive symptoms, and anxiety symptoms. Additionally, we presented ikigai scores for specific sociodemographic groups of interest. Results: Cronbach’s alpha for the Ikigai-9-G equaled 0.88. The results of confirmatory factor analysis supported the original three-factor model as initially proposed. A higher sense of ikigai was associated with less depressive symptoms (r = −0.43, p < 0.001), less anxiety symptoms (r = −0.39, p < 0.001), higher health-related quality of life (r = 0.42, p < 0.001), higher happiness levels (r = 0.62, p < 0.001), and higher satisfaction with life levels (r = 0.57, p < 0.001). Conclusion: The Ikigai-9 scale is a psychometrically sound tool offering the possibility for assessing ikigai among German speakers. Additional translation and validation studies are required to facilitate comparisons across different countries.

1. Introduction

Within Japanese culture, the concept of “ikigai” denotes the presence of a life purpose or a rationale for existence [1]. Mathews translates it as follows: “that which most makes one’s life seem worth living” [2]. Ikigai can be viewed as a comprehensive construct encompassing the dimensions of meaning, motivations, and values in life [3,4,5].

In the past years, more and more studies have explored the determinants and consequences of ikigai. For example, one study showed that higher levels of ikigai are associated with a lower risk of incident functional disability based on data from a prospective cohort study of Japanese individuals aged 70 years and over [6]. Another study showed an association between being frail and lower levels of ikigai among community-dwelling older adults in Japan [7]. Another longitudinal study of Japanese individuals aged 65 years and over showed that ikigai (compared to not having ikigai) is associated with 36% lower risk of developing dementia during a 3-year follow-up [8]. Moreover, this former study showed that the presence of ikigai was associated with higher happiness, higher life satisfaction, and some favorable social outcomes such as social participation, whereas it was associated with decreased hopelessness and fewer depressive symptoms [8].

An additional recent study also revealed that ikigai is positively associated with social support among university participants [9]. Moreover, this previous study showed that ikigai can mediate the link between social support and problematic smartphone use [9]. Another recent mixed methods study also demonstrated that health is the most common source of ikigai based on data from older adults in Japan [10]. Other research revealed that a lack of ikigai was associated with an increased risk of all-cause mortality based on data from a prospective cohort study of Japanese adults [11]. Overall, the aforementioned studies showed that ikigai can contribute to health outcomes as well as subjective well-being.

While some studies (e.g., [9]) used single-items to quantify ikigai (presence of ikigai: yes or no), a more sophisticated tool is already available: The Ikigai-9 developed by Imai et al. is an instrument that has been initially developed and validated in Japanese [12]. This tool is designed to assess ikigai by exploring three dimensions: (1) optimistic and positive emotions regarding life, (2) active and positive attitudes toward one’s future, and (3) recognition of the meaning of one’s existence.

A recent study translated the Ikigai-9 into English and validated this version [13]. Other very recent validation studies stem from France [14] and Turkey (preprint: [15]). However, thus far, a German version of the Ikigai-9 is missing. It is also worth noting that the concept of “ikigai” does not have a counterpart in German culture, and there are no instruments for measuring such a concept in the German language (e.g., developed by German researchers). Thus, our aim was to translate and validate a German version of the Ikigai-9 (and present ikigai scores for certain groups of interest).

This is important because it enables more extensive cross-cultural investigations and enhances comprehension of the Ikigai concept within Germany. Moreover, it can contribute to a better understanding of the antecedents and consequences (e.g., health outcomes or well-being) of ikigai within German-speaking populations. This may contribute to, among other things, successful aging in Germany.

2. Materials and Methods

2.1. Sample

We used data originating from a sample of individuals in Germany selected based on quotas, covering ages 18 to 74 (n = 5000). The data gathering process took place during the months of August and September in the year 2023.

Regarding participant recruitment, the task was undertaken by the professional market research company Bilendi, Berlin, Germany (ISO certified, 26362). The selection of participants occurred within an online pool, using quota criteria to guarantee a representation mirroring the broader adult population of Germany in terms of age, gender, and geographical location (i.e., state).

Every participant provided their consent before engaging in the study. Furthermore, this study received ethical approval from the Local Psychological Ethics Committee at the University Medical Center Hamburg-Eppendorf (LPEK-0629).

2.2. Translation Process

The translation process closely followed established guidelines [16]. Specifically, a respected professional institution (tolingo) handled the translation task. To elaborate, the professional institution consisted of two native German speakers; one possessed prior familiarity with the research domain, while the other was “naive” in this context, having no previous exposure to this field. These individuals independently translated the content into German. Subsequently, we (AH, HHK) harmonized the translated versions. During this phase, assistance was provided by a psychologist (LZ) and a Japanese native speaker (MH) who has been living in Germany for an extended period. This native Japanese speaker is very familiar with German culture and speaks fluent German.

For the subsequent translation into Japanese, two Japanese native speakers (back-translators) were employed (again, from tolingo); one possessed prior familiarity with the research area, and the other was “naive” (i.e., without prior knowledge in this research field). They independently translated the unified version into Japanese. Discrepancies arising between the versions were initially resolved through discussions (AH, HHK, LZ, MH), and any remaining issues were addressed by consulting Professor Imai (TI), the originator of the Ikigai-9 instrument. The German version of the Ikigai-9 (in short: Ikigai-9-G) can be found in

Table 1. German version of the Ikigai-9.

Bitte sagen Sie uns, wie Sie sich in Ihrem Alltag fühlen.

Bitte wählen Sie jeweils eine Antwortmöglichkeit.

Ich fühle mich häufig glücklich.

Ich möchte etwas Neues lernen oder beginnen.

Ich denke, ich tue etwas Nützliches für andere Menschen und die Gesellschaft.

Ich bin entspannt und gelassen.

Ich interessiere mich für verschiedene Dinge.

Ich denke, dass meine Existenz für etwas oder jemanden notwendig ist.

Mein Leben ist reich und erfüllend.

Ich möchte mein Potenzial weiterentwickeln.

Ich denke, dass ich Einfluss auf jemanden habe.

Anmerkung 1: Die fünf Antwortmöglichkeiten sind: “Trifft sehr zu”, “Trifft eher zu”, “Trifft etwas zu”, “Trifft eher nicht zu” und “Trifft nicht zu”.

Note: Item 1 refers to the first statement (“Ich fühle mich häufig glücklich”), item 2 refers to the second statement, and so on.

. This tool consists of nine items (with five answer categories: from 1 to 5). A sum score was generated. The sum score ranges from 9 to 45, with higher values reflecting higher levels of Ikigai.

2.3. Other Measures

Similar to prior research (e.g., [13,14,15]), pairwise correlations of the Ikigai-9-G with life satisfaction, happiness, health-related quality of life, depressive symptoms, and anxiety symptoms were calculated.

Life satisfaction was measured using the Satisfaction with Life Scale [17]. This is an established and widely used tool (e.g., [18,19]) consisting of five items. The sum score ranges from 5 to 35, with higher values reflecting higher life satisfaction levels.

Happiness was measured using the well-known Subjective Happiness Scale [20], consisting of four items. One item was recoded prior to averaging the four items. The resulting score ranged from 1 to 7, with higher values indicating higher happiness levels.

Moreover, health-related quality of life was measured using a visual analogue scale (called EQ-VAS [21]—a widely used tool), reflecting self-rated health according to the respondent’s preferences, with a scale ranging from 0 (indicating the worst imaginable health) to 100 (indicating the best imaginable health).

Depressive symptoms were assessed using the established Patient Health Questionnaire-9 (PHQ-9) [22], which has nine items. A sum score was created that ranged from 0 to 27 (higher values signifies more depressive symptoms).

The well-known Generalized Anxiety Disorder-7 (GAD-7) was used to quantify anxiety symptoms. It has seven items [23]. We summarized them and the resulting score ranged from 0 to 21, with higher values indicating more anxiety symptoms.

2.4. Statistics

To examine the underlying three-factor structure of the instrument, a confirmatory factor analysis (CFA; maximum likelihood) was conducted. Model adequacy was assessed through several fit indices (employing Satorra–Bentler-adjustment to account for non-normality [24]), including the Chi² statistic, Root Mean Square Error of Approximation (RMSEA), Standardized Root Mean Square Residual (SRMR), the Normed Fit Index (NFI), the Relative Fit Index (RNI), the Comparative Fit Index (CFI), the Incremental Fit Index (IFI), and McDonald’s Centrality Index (MCI). The criteria for good measurement properties followed existing recommendations [25]. We utilized widely used fit indices. We also used different indices to ensure a certain robustness of the results.

To assess the concurrent validity, correlation coefficients (in terms of Pearson’s r) between the Ikigai-9 and life satisfaction, happiness, health-related quality of life, depressive symptoms, and anxiety symptoms were computed. The classification for concurrent validity was delineated as follows: exceptionally high if the correlation reached 0.9 or exceeded it, high when in the range of 0.7 to 0.9, moderate when spanning 0.5 to 0.7, low when encompassing 0.3 to 0.5, and negligible when falling below 0.3 [26].

The reliability of the instrument was evaluated using both Cronbach’s alpha and McDonald’s omega for the Ikigai-9-G. Excellent internal consistency was defined by values equal to or exceeding 0.9. A strong and satisfactory internal consistency was denoted by values of 0.8 or higher and 0.7 or higher, respectively [27].

No missing values were identified in the dataset, thus obviating the need for using techniques for dealing with missing data such as multiple imputation.

The analysis was performed using Stata 18.0 MP (Stata Corp., College Station, TX, USA). Within this study, the Stata tools “validscale” [28] and “omegacoef” [29] were employed, with the former facilitating the performance of the statistical analyses required to validate a tool (e.g., Cronbach’s alpha or CFA) and the latter facilitating the computation of McDonald’s omega coefficient.

3. Results

3.1. Sample Characteristics

The participants had a mean age of 46.9 years (standard deviation: 15.3), ranging from 18 to 74 years (18 to 29 years: 17.6% of the respondents; 30 to 39 years: 17.7% of the respondents; 40 to 49 years: 17.5% of the respondents; 50 to 59 years: 22.6% of the respondents; 60 to 74 years: 24.6% of the respondents). Furthermore, 50.8% of the participants identified as female (49.0% identified as male and 0.2% as diverse).

The majority of the participants had a medium education level (59.7%). In total, 57.9% of the respondents lived together with a partner/spouse, 11.0% of the respondents had a migration background, and 48.4% of the respondents were full-time employed (20.0% of the respondents were retired, and 31.6% of the respondents had another occupational status). The mean self-rated health equaled 2.3 (SD: 0.8) on a single-item scale ranging from 1 = very good to 5 = very poor. More precisely, 13.0% of the respondents rated their health as very good, 47.9% of the respondents as good, 30.5% of the respondents as average, 7.6% of the respondents as poor, and 1.1% of the respondents as very poor. The distributions of age, gender, and federal state in our sample corresponded to those of the general German population.

The average score of the German version of the Ikigai-9 was 31.9 (SD: 7.0, ranging from 9 to 45; men: 31.9, SD: 7.0; women: 31.9, SD: 6.9; diverse: 27.0, SD: 10.0). Stratified by age range, it was as follows: the average score of the German version of the Ikigai-9 equaled 31.5 (SD: 7.0) among individuals aged 18 to 29 years (30 to 39 years: 32.4, SD: 7.2; 40 to 49 years: 32.2, SD: 7.0; 50 to 59 years: 31.4, SD: 6.9; 60 to 74 years: 31.8, SD: 6.7). A histogram of scores for the subscales is also displayed in Figure S1, and a description of the items is provided in Table S1.

Divided by educational level (CASMIN classification [30]), the average score of the German version of the Ikigai-9 equaled 29.7 (SD: 7.2) among individuals with a primary education. The average score of the German version of the Ikigai-9 was 31.4 (SD: 6.7) among individuals with a secondary education, and the average score of the German version of the Ikigai-9 was 33.5 (SD: 7.0) among individuals with a tertiary education.

Furthermore, the average score of the German version of the Ikigai-9 was 31.9 (SD: 6.9) among individuals without a migration background, and it was also 31.9 (SD: 7.1) among individuals with a migration background. Stratified by employment status, the average score of the German version of the Ikigai-9 was 32.6 (SD: 6.9) among individuals being full-time employed, whereas the score equaled 30.8 (SD: 6.8). Furthermore, the average score of the German version of the Ikigai-9 equaled 31.4 (SD: 7.0) among individuals with another occupational status (it may be worth noting that the average score of the German version of the Ikigai-9 was 27.5, SD: 6.9 among jobseekers/unemployed individuals).

Stratified by family situation, while the average score of the German version of the Ikigai-9 equaled 30.2 (SD: 6.9) among singles, it was also 30.2 (SD: 7.0) among divorced individuals. Moreover, the average score of the German version of the Ikigai-9 was 31.7 (SD: 7.0) among widowed individuals, and it was 32.8 (SD: 6.8) among individuals living together (with partner or spouse). Lastly, the average score of the German version of the Ikigai-9 equaled 32.3 (SD: 7.0) among individuals living separated from their spouse or partner.

3.2. Reliability

Internal consistency is displayed in

Table 2. Internal consistency index for ikigai and each ikigai dimension.

	Ikigai-9-G	Optimistic and Positive Emotions Regarding Life Subscale	Active and Positive Attitudes toward One’s Future Subscale	Recognition of the Meaning of One’s Existence
Cronbach’s alpha	0.88	0.84	0.76	0.77
McDonald’s omega	0.88	0.84	0.77	0.77

. Cronbach’s alpha for the German version of the Ikigai-9 equaled 0.88. McDonald’s omega also equaled 0.88. Cronbach’s alpha for the optimistic and positive emotions regarding life subscale equaled 0.84 (McDonald’s omega: 0.84). Moreover, it was 0.76 (McDonald’s omega: 0.77) for the active and positive attitudes toward one’s future subscale and 0.77 (McDonald’s omega: 0.77) for the recognition of the meaning of one’s existence subscale.

3.3. Validity

3.3.1. Construct Validity of the Ikigai-9-G

The proposed three-factor solution of the Ikigai-9 underwent confirmatory factor analysis, indicating that the data did adhere to the model suggested by Imai et al. [12]. Each item loaded onto its respective factor was based on the original validation study conducted in the Japanese context [12]. The model demonstrated satisfactory fit in our current sample (e.g., CFI = 0.955, RMSEA = 0.076, SRMR = 0.051). Further details are given in

Table 3. Confirmatory factor analysis of data (three-factor solution).

Chi2	df	RMSEA	SRMR	NFI	RNI	CFI	IFI	MCI
712.94	24	0.076	0.051	0.953	0.955	0.955	0.955	0.933

.

Satorra–Bentler-adjusted goodness-of-fit indices were produced.

Moreover,

Table 4. Standardized factor loadings of the Ikigai-9-G and pairwise correlations (Pearson’s r) between the three subscales (SE in parentheses).

	Optimistic and Positive Emotions Regarding Life Subscale	Active and Positive Attitudes toward One’s Future Subscale	Recognition of the Meaning of One’s Existence
Item 1	0.81 (0.01)
Item 4	0.71 (0.01)
Item 7	0.88 (0.01)
Item 2		0.71 (0.01)
Item 5		0.64 (0.01)
Item 8		0.82 (0.01)
Item 3			0.70 (0.01)
Item 6			0.74 (0.01)
Item 9			0.75 (0.01)
Subscale: optimistic and positive emotions regarding life	1
Subscale: active and positive attitudes toward one’s future	0.52	1
Subscale: recognition of the meaning of one’s existence	0.66	0.59	1

Notes: all items were highly significant (p < 0.001).

displays the standardized factor loadings for the three-factor structure and pairwise correlations between the subscales. The standardized factor loadings mainly ranged from 0.7 to 0.8. Furthermore, moderate positive correlations were observed between the three subscales (see Table 4 for further details).

3.3.2. Concurrent Validity of the Ikigai-9-G

Results of the pairwise correlations are presented in

Table 5. Examination of correlation between scales: concurrent validity analysis (n = 5000).

	1	2	3	4	5	6
1: Depressive symptoms (PHQ-9)	1
2: Anxiety symptoms (GAD-7)	0.85 ***	1
3: HRQoL (EQ-VAS)	−0.51 ***	−0.44 ***	1
4: Happiness (SHS)	−0.59 ***	−0.56 ***	0.51 ***	1
5: Life satisfaction (SWLS)	−0.50 ***	−0.46 ***	0.48 ***	0.74 ***	1
6: Ikigai (Ikigai-9-G)	−0.43 ***	−0.39 ***	0.42 ***	0.62 ***	0.57 ***	1

Notes: Pearson correlations are shown, *** p < 0.001; Bonferroni-adjusted significance levels are calculated.

. More precisely, pairwise correlations from Ikigai-9-G with life satisfaction, happiness, health-related quality of life, depressive symptoms, and anxiety symptoms were calculated and presented. Higher levels of Ikigai were associated with less depressive symptoms (r = −0.43, p < 0.001), less anxiety symptoms (r = −0.39, p < 0.001), higher health-related quality of life (r = 0.42, p < 0.001), higher happiness levels (r = 0.62, p < 0.001), and higher satisfaction with life levels (r = 0.57, p < 0.001). Further details regarding the correlations between the constructs are shown in Table 5.

4. Discussion

The aim of our study was to translate and validate the German Ikigai-9 version (Ikigai-9-G) for research use in German-speaking populations, and to confirm the concurrent validity of the Ikigai-9-G (and to present ikigai scores for certain groups of interest). This study represents the first validation study of the German version of Ikigai-9 and therefore extends our current knowledge in this research field. Our key findings were as follows: A high reliability of the Ikigai-9 has been shown in our current work, and the original three-factor model was confirmed. Moreover, concurrent validity has been demonstrated in our present work. Furthermore, ikigai scores for specific sociodemographic groups of interest have been shown.

Confirmatory factor analysis of the Ikigai-9-G substantiated the three-dimensional structure initially suggested by Imai et al. [12], which encompasses facets related to positive emotions towards one’s life, positive attitudes towards one’s future, and the acknowledgement of the meaning of one’s existence. Confirming the structure ensures the integrity of the tool and enables valid and reliable assessments in different linguistic and cultural contexts. This is crucial for maintaining the usefulness of the instrument and the validity of the results obtained. A very recent study confirmed a three-factor structure of the Ikigai-9 in France [14], whereas two other studies (UK [13] and Turkey [15]) favored a 1-factor solution (e.g., confirmatory factor analysis of the three-factor solution in UK: RMSEA = 0.14, CFI = 0.91, TLI = 0.87 [13])).

The study from France explains the differences in the number of factors by the translation of item 4 (“I have room in my mind”). The Turkish version also translated the item from the English version. This could therefore possibly explain the differences. In English, respondents could refer to the ability to learn new things, but this translation does not seem to match the ability to have a calm head [14]. In our study, we translated the item from the Japanese version. Moreover, we extensively discussed the cultural meaning of this question with a Japanese native speaker (MH). Afterwards, we discussed item 4 with Professor Imai (TI; worth repeating: the developer of the Ikigai-9 instrument). Regarding item 4, he referred to “ゆとり” (Yutori)” (a unique concept in Japanese encompassing a relaxed, spacious approach, not feeling rushed or overloaded). He (TI) agreed with our final proposed version.

The validation studies conducted in the UK and Turkey [13,15] demonstrated that higher levels of ikigai are associated with better mental well-being and fewer depressive symptoms. This is in accordance with our present study. Furthermore, this supports related research demonstrating an association between purpose in life and mental health based on a meta-analysis [31]. Such an association between ikigai and mental health may reflect that individuals strive to uphold a comprehensive sense of global meaning [32]. If life events introduce misalignments with this global meaning, individuals may initiate efforts and strategies to diminish the disparity [31]. Unsuccessful attempts to rectify this misalignment could lead to enduring distress [31].

The average scores of the German version of the Ikigai-9 were a bit lower to the ones provided by a study of a UK general population [13] (32.9 in total, SD: 7.9; men: 32.4, SD: 7.4; women: 33.3, SD: 8.4) and a Japanese cohort [12] (33.3, SD: 5.4 in total; men: 33.1, SD: 5.4; women: 33.4, SD: 5.4). For example, the effect size (Cohen’s d) for the total sample (UK vs. Germany) was d = 0.14 in absolute terms (Germany vs. Japan: d = 0.20 in absolute terms). However, such potential differences (between our data and findings from UK and Japan [12,13]) should be interpreted with great caution due to the different characteristics of the sample. For example, the study conducted by Imai et al. focused on individuals aged 60 to 85 years [12]. Moreover, the sample from the UK study also differed a bit from our study (n = 349, online questionnaire advertised via Prolific; mean age was 34.7 years, SD: 12.0 years, 18 to 72 years; 50.7% female).

Similarly to prior research [13,14,15], concurrent validity as well as high reliability was demonstrated in our current work. The concurrent validity also shows the accuracy in assessing our intended construct.

The Turkish version also showed comparable correlations between Ikigai and mental health [15] (in terms of anxiety symptoms as well as depressive symptoms). Moreover, it may be worth noting that the Japanese version had a very similar Cronbach’s alpha for the Ikigai-9 (0.87) compared to our study (0.88) [12]. The Turkish version also reported a Cronbach’s alpha of 0.87. Only the study from France had somewhat lower values [14] (e.g., Ikigai-9: both Cronbach’s alpha and McDonald’s omega equaled 0.78).

Overall, the favorable psychometric characteristics of the Ikigai-9-G encourage the use of this measure in future studies. For example, the potential protective effects of ikigai-9 could be explored in German-speaking populations. This may have the potential to reduce the number of suicides [33] or reduce the number of cardiovascular diseases [34]. Future studies could also explore the underlying mechanisms of how ikigai (quantified using the Ikigai-9-G) is associated with health-related outcomes. For example, a former study assumed that ikigai may contribute to favorable lifestyle factors (not smoking, low alcohol intake) and satisfaction with one’s own job [35].

Moreover, the validation of the German Ikigai-9 version can enable cross-cultural comparisons (e.g., within Europe or comparisons between countries from different continents). Such comparisons can help in facilitating the understanding of ikigai globally. This is required since several studies examining ikigai are restricted to selective samples (e.g., convenience or clinical samples) in some countries, which makes it difficult to generalize the existing findings (see [36]).

Some strengths and weaknesses are worth acknowledging. First, a very large, quota-based sample (representative in terms of age, sex, and state) was used (ensuring a certain generalizability of our findings). A very thoroughly conducted translation process was conducted, which was in accordance with existing recommendations. In doing so, the authors also closely coordinated with the developer of the Ikigai-9. Furthermore, this is the first validation study of the German Ikigai-9 version. Our study also included confirmatory factor analysis and correlation analysis. It is important to recognize that this study followed a cross-sectional design, which prevented the calculation of test–retest reliability. Our study is confined to participants between the ages of 18 and 74. Consequently, there is a need for future research encompassing individuals aged 75 and above, as well as adolescents. This could enhance our understanding of ikigai across very different life stages among German speakers.

5. Conclusions and Future Research

In conclusion, the German Ikigai-9 version is a psychometrically sound tool. It offers a practical tool for assessing ikigai among German speakers. Upcoming longitudinal studies should also explore the test–retest reliability of ikigai. For example, it would be of interest to know whether ikigai can change within individuals over time—which could help to develop interventional strategies. Such strategies to enhance ikigai could assist in maintaining health and well-being.

Regarding future research, studies exploring the antecedents and the consequences of ikigai would be of interest. For example, moderating (e.g., sex or education) and mediating factors (e.g., general self-esteem) could be explored in the association between ikigai and health-related outcomes (such as frailty, cognitive or functional decline, immobility, visual or hearing impairment, health-related quality of life, or mental health) or well-being outcomes (such as happiness, quality of life, or satisfaction with life) in German speaking populations.