Death Literacy Index Short Form: Cultural Adaptation and Psychometric Evaluation of the Turkish Version

Abstract

The aim of this study was to adapt the short form of Death Literacy Index (DLI-9) into Turkish and to examine its psychometric properties. This study has a methodological cross-sectional design. The study was conducted with a sample of 400 adults across Türkiye during October-November. Content Validity Index, Exploratory Factor Analysis (EFA), Confirmatory Factor Analysis (CFA), Convergent and Discriminant Validity Analyses, test-retest reliability, Cronbach’s α-coefficient, item-total-score correlation, 27% upper-lower-group item analysis and Hotelling-T² test were used in data analysis. In the EFA analysis, the scale consisted of 2 factors. The original two-factor structure of the scale was confirmed by CFA. CFA model fit values were found as CMIN/DF = 2.078, RMSEA = 0.074, RMR = 0.077, SRMR = 0.0455, CFI = 0.960, NFI = 0.927, TLI = 0.945, GFI = 0.946, and AGFI = 0.906. The total Cronbach’s α reliability coefficient of the DLI-9 was found to be 0.84. This study indicates that scale is a reliable tool for evaluating death literacy in the Turkish population.

Keywords

death death literacy psychometrics reliability validity

Introduction

Death is a universal and inevitable reality that people have to cope with in their lives (Çekiç et al., 2024). Death is not only an individual experience but also a social and cultural phenomenon. Death, encompassing various interpretations such as the unknown and annihilation, remains a taboo in numerous nations and cultures (Serra-Sutton et al., 2024). The removal of death from being a taboo, seeing it as a natural part of life, and being able to talk about death are related to the level of death literacy (DL) (Li et al., 2024).

The DL concept, developed as a result of years of research in Australia, encompasses all skills related to knowledge, experience, beliefs, and practices concerning death (Noonan et al., 2016). Understanding death, improving individuals’ quality of life, preparing for death, and determining the mourning processes, which constitute the content of palliative care, are included within the scope of death literacy (Leonard et al., 2022; Van Dinther et al., 2025). In this context, the Death Literacy Index (DLI) was developed by Leonard et al. (2022) to evaluate death and post-death processes, taking into account the comprehensive views and experiences of many experts and participants with experiences related to death.

The DLI consists of 29 statements in a 5-point Likert-scale, encompassing the sub-dimensions of “practical knowledge (talking support, hands-on care), experiential knowledge, factual knowledge, and community knowledge (others can help me provide end-of-life-care, support-groups in my community)” (Leonard et al., 2022). As DL, a new concept, has been understood, interest in scale has gradually increased, and social and cultural adaptations have begun to be made rapidly. It has been reported that the validity and reliability of the scale, which has been validated in the United Kingdom (2022), China (2023), Sweden (2023) and Türkiye (2024), is still being culturally adapted in many societies (Che et al., 2023; Graham-Wisener et al., 2022; Johansson et al., 2023; Semerci et al., 2024).

The authors developing the DLI found that, based on the feedback from researchers making cultural adaptations, there are generally very few cultural differences regarding DL. Based on the feedback and suggestions they received, the authors developed a shorter form of the DLI, without altering its original version, in order to improve the scale’s readability and applicability (Noonan et al., 2024). It is believed that researching individuals’ DL levels with this brief and practical tool will facilitate the work of all professionals in the fields of health and social sciences. This study was conducted with the aim of adapting the newly developed short form of the Death Literacy Index (DLI-9) into Turkish to evaluate DL in the Turkish population.

Methods

Study Design

The design of this study is cross-sectional and methodological.

Participants

The population of this study consisted of individuals aged 18 and over from across Türkiye. The criteria for inclusion in the study were being literate, consenting to participate in the study, and being 18 years old or older. According to DeVellis (2017), psychometric studies are reported to have a sample size of 200 for moderate, 300 for good, and 500 for excellent. The study was completed with 400 individuals who met the inclusion criteria, using the snowball sampling method.

As a result of analysis conducted to determine adequacy of sample size for validity and reliability analyses, Kaiser-Meyer-Olkin (KMO) coefficient was 0.819 and Bartletts test was χ² = 623.397; p < .001. According to these results, it was concluded that sample size was sufficient for further analysis.

Data Collection Tools

The data were collected using the Personal Information Form and DLI-9.

Personal Information Form

In this form prepared by researchers, there are 8 questions including age, gender, educational, marital, employment status, income status, place of residence and death of a relative.

DLI-9

The scale was developed by Noonan et al. (2024). The scale consists-of 9-items.The five-point Likert type scale consists of 2 sub-factors. Factor 1 (4 items) addresses the private sphere and Factor 2 (5 items) addresses the public sphere. Although it has been shown that the DLI-9 has two factors, it is recommended to use it as a single scale with nine items. The Cronbach’s α-coefficient of the DLI-9 is 0.87, Cronbach’s α-coefficient for Factor 1 is 0.82, and Cronbach’s α-coefficient for Factor 2 is 0.87, indicating high internal reliability.

Procedure

There are many methods for adapting scales to different cultures. The translation and cultural adaptation process of the scale was carried-out in accordance with the guidelines published by Professional Society for Health Economics and Outcomes Research (ISPOR) (Wild et al., 2005). Firstly, permission for the use of the scale was obtained from the scale owner via e-mail. Then, to ensure the validity of the language, the scale was translated from English-to-Turkish by two independent translators who were fluent in-both languages. Translation was reviewed and evaluated by researchers. The scale was then evaluated by a Turkish language expert in terms of grammar and comprehensibility. Necessary corrections were made by researchers. The Turkish version of the scale was retranslated into English by two different independent translators. After back translation, it was confirmed that the Turkish version of the scale was very similar to the English version. Subsequently, to evaluate the content validity of the scale, the opinions of total of 4 experts from the fields of public health nursing, internal medicine nursing, psychiatric nursing and basic medical sciences were consulted. After expert opinion, the Content-Validity-Index (CVI) was calculated and minor corrections were made. Afterwards, a pilot study was conducted with 30 individuals with similar characteristics to the sample. In the pilot study conducted to evaluate the readability and comprehensibility of the scale, no negative feedback was received, and no corrections were made. The final version of the scale was created. Those who had participated in the pilot study weren’t included in the study-sample.

Data Collection

The data were collected online by the researchers between October 20 and November 20, 2024, using the Personal Information Form and the Turkish version of scale via Google Forms. Before starting the survey questions in the online form, a written explanation about the study was provided, and a question was asked to determine whether they were willing to participate in the research.

Ethics

Permission for the use of the scale was obtained from the owner of scale via e-mail. Ethics committee approval (17.10.2024/Decision-no:70–08) was obtained for the research. Before starting the survey questions in the online form, a written explanation about the study was provided. Consent was obtained by asking a question regarding their willingness to participate in the study. In this study, scientific and universal principles were followed. The study was conducted in accordance with the Declaration of Helsinki.

Analysis

IBM SPSS (v. 25) and AMOS (v. 21) software packages were used to analyse the data. Statistical significance level was accepted as p < .05. Descriptive statistics were provided for the participants’ demographic characteristics. The distribution of the data was analysed in terms of skewness and kurtosis and it was determined that the data showed a normal distribution between ±2. For validity, CVI, Exploratory Factor Analysis (EFA), and Confirmatory Factor Analysis (CFA) were conducted. Polit and Beck CVI method was used to determine the content validity of the scale-items. Four experts were consulted for the scale’s CVI. EFA was conducted with 200 data points to determine the construct validity of the scale. The original two factor structure of scale was confirmed by CFA with 200 different data. Before starting the CFA in AMOS, it was evaluated whether the data were normally distributed (multivariate), whether there was multicollinearity and whether the sample size was sufficient. All assumptions were met. Maximum Likelihood estimation method and covariance matrix were used for CFA. For reliability, test-retest reliability, Cronbach’s α-coefficient, item-analysis based on item-total-score correlation and item-analysis based on 27% upper-lower-groups were performed. Hotelling-T² test was applied to determine response bias of the scale. Average-Variance-Extracted (AVE) and Composite-Reliability (CR) were calculated for the validity of convergence and divergence.

Results

The mean age of the participants was 35.31 ± 17.90 years (18–88 years). 53.3% of the participants were female, 57% were single, 72% were high school graduates, 70% were not employed, 60% had an income-equal to their expenses, 60.5% lived in urban areas, and 73.5% had experienced the death of a close relative.

Validity Analyses

Content Validity

The opinions of 4 experts were consulted for the content validity of scale. Item-Content Validity Index (I-CVI) and Scale-Content Validity Index (S-CVI) were calculated using the Polit and Beck CVI method. I-CVI and S-CVI/Ave were set as 1.00.

EFA

For EFA, correlation matrix (Principal-Component-Analysis) method, ‘varimax’ rotation method were applied. Eigenvalue was determined as 1.00 and the factor loading as 0.32. According to the EFA result, the scale had 2 factors and a total variance of 56.710%. The first factor consisted of 4 items with factor-loadings between 0.517 and 0.832. The second factor consisted of 5 items with factor-loadings between 0.433 and 0.844. The factor loadings, eigenvalues and explained variances of the sub-dimensions obtained in the EFA of the scale are provided in Table 1.

Table 1.

Exploratory Factor Analysis of the Turkish Version of DLI-9.

Factor 1Practical and experiential knowledge			Factor 2Factual and community knowledge
Item1	How able are you to talk to a grieving person about their loss?	0.649	Item5	To what extent do you agree that you know enough about the rules and regulations when a person dies at home?	0.544
Item2	How able are you to feed or help a person to eat?	0.517	Item6	To what extent do you agree that you know enough about the healthcare system to find the support that a dying person needs?	0.792
Item3	Previous experiences of grief, losing someone, or other important life events have made me more emotionally prepared to support others with death dying and bereavement	0.832	Item7	To what extent do you agree that you know how to access palliative care?	0.844
Item4	Previous experiences of grief, losing someone, or other important life events have made me better prepared to face similar challenges in the future	0.809	Item8	If I were to provide end-of-life care for someone, I know people who could help me to get support that is culturally appropriate for a person	0.773
			Item9	There is support in my community for people who are caring for a dying person	0.433
Eigenvalue		1.126			3.978
Explained variances		12.511			44.199
Total explained variances (%)		56.710

CFA

CFA was conducted on the data to confirm two-factor construct validity of the Turkish version of scale. As a result of the CFA, the factor loadings of 9 items were found to be between 0.55 and 0.83. CFA model fit values were found as CMIN = 54.032, DF = 26, CMIN/DF = 2.078, RMSEA = 0.074, RMR = 0.077, SRMR = 0.0455, CFI = 0.960, NFI = 0.927, TLI = 0.945, GFI = 0.946, and AGFI = 0.906.

Factor loadings of scale-items related to CFA are shown by the path diagram (Figure 1).

Figure 1.

Path diagram.

Convergent and Discriminant Validity Analyses

For the first sub-dimension (Practical and Experiential Knowledge), the CR value was found to be 0.801, and for the second sub-dimension (Factual and Community Knowledge), it was found to be 0.848. The AVE values for the sub-dimensions were determined to be 0.510 (1st sub-dimension) and 0.530 (2nd sub-dimension), respectively. The results of the analysis showed that the CR was higher than the AVE, confirming that the scale has both discriminant and convergent validity.

Reliability Analyses

Test-Retest Analysis

Turkish-version of theDLI-9 was administered to 30 individuals aged 18and over, representing the population, with an interval of 3 weeks between sessions. These 30 participants weren’t included in the overall sample. The correlations between results of the first-second administrations of DLI-9, and its subscales were calculated, and a strong, highly significant positive-correlation was observed (Table 2).

Table 2.

Test-Retest Results Based on Overall DLI-9 and Its Subscales.

	ICC	95% confidence interval		p
	ICC	Lower limit	Upper limit	p
Practical and experiential knowledge	0.992	0.987	0.995	0.000
Factual and community knowledge	0.994	0.986	0.996	0.000
Death literacy Index-9	0.996	0.993	0.998	0.000

ICC; Intraclass Correlation Coefficient.

Cronbach’s α-Reliability Coefficient, Item Analysis

The overall Cronbach’s α-reliability coefficient of the DLI-9 was 0.847. The Cronbach’s α-reliability coefficients of the sub-dimensions of the scale and the item-analysis based on the item total score correlation to determine the internal consistency reliability of the scale are provided in Table 3. It was found that the item total score correlations of the scale ranged between 0.475 and 0.619, and the item-sub-dimension score correlations ranged between 0.485 and 0.683.

Table 3.

Cronbach α Reliability Coefficient and Item Analysis of DLI-9.

Sub-dimensions	Item number	Corrected item total correlation	Item-sub-dimension total correlation	Cronbach α	Mean ± SD
Factor 1	Item 1	0.475	0.504	0.766	3.30 ± 1.32
	Item 2	0.494	0.485		3.45 ± 1.40
	Item 3	0.596	0.646		3.44 ± 1.32
	Item 4	0.587	0.642		3.42 ± 1.31
Factor 2	Item 5	0.600	0.581	0.822	3.01 ± 1.36
	Item 6	0.619	0.683		3.04 ± 1.26
	Item 7	0.591	0.659		2.66 ± 1.35
	Item 8	0.618	0.675		3.16 ± 1.28
	Item 9	0.501	0.486		3.42 ± 1.23
Total score				0.847	3.20 ± 0.88

Abbreviation: SD, standard deviation.

In the item analysis based on the upper and lower 27% groups, the difference between the means of the upper and lower groups was determined using an independent-samples-t-test. It was found that the items of the scale had a discriminative feature in the researched subject (p < .001). As a result of the Hotelling-T² test conducted to evaluate whether the individuals’ responses to the scale-items were equal, Hotelling-T² = 175.891 p < .001 was found.

Discussion

DL is the knowledge and skills that enable understanding the care options during the final stages of life and the dying process, and making informed decisions based on these options (Noonan et al., 2016). The evaluation of DL is important in terms of developing care options during the end-of-life and death process. The DLI was developed by Leonard et al. (2022), and adapted into Turkish by Semerci et al. (2024). It would be useful to use a short survey to evaluate DL (Noonan et al., 2024). Accordingly, in this study, the DLI-9 developed by Noonan et al. was adapted to Turkish culture and its psychometric properties were examined. This study is the first study on the adaptation of the DLI-9 to different cultures.

Validity Analyses of the DLI-9

Content Validity

Translation and cultural adaptation process of the DLI-9 was carried out in accordance with the guidelines published by the ISPOR (Wild et al., 2005). Content-validity was used to determine the extent to which entire scale and each item in it represents the construct to be measured (Çam & Baysan-Arabaci, 2010). Polit and Beck’s (2006) CVI, one of the content validity methods, rates expert opinions as (1)'Not appropriate’, (2)'Somewhat appropriate’, (3)'Quite appropriate’, and (4)'Extremely appropriate’. In this method, the number of experts marking options (3) and (4)is divided by total number of experts to obtain I-CVI and S-CVI. If the number of experts is between 3 and 5, these values are expected to be 1.00 (Polit & Beck, 2006). The I-CVI and, S-CVI values of DLI-9 translated into Turkish, which were calculated using 4 expert evaluations, were found to be high. Additionally, no significant issues regarding the clarity of the scale items were reported by the participants in the pilot study. These results supported that the translation process was successful and the DLI-9 had sufficient content validity in the Turkish sample.

Construct Validity

Before examining factor structure of a scale, KMO-test is applied to evaluate the adequacy of the sample for factor-analysis, and Bartlett-test is applied to assess its suitability. To conduct factor-analysis, KMO-value is expected to be above 0.60, while a value above 0.80 indicates very-good-fit. Bartlett-test result of p < .05 indicates that correlation matrix is significant, the dataset is appropriate, and the sample size is adequate (Karagöz & Bardakçı, 2020; Kamiloglu & Vural, 2022). In this study, the KMO and Bartlett tests showed that, the sample size was sufficient and the dataset was suitable for factor analysis.

In this study, EFA and CFA were applied to evaluate construct-validity. In EFA, it is recommended that factor loadings be at least above 0.32. In determining the factors, those with an eigenvalue greater than 1.00 are considered significant, and the high variance ratios enhance the strength of the scale’s factor construct. In the literature, it is stated that a variance ratio between 40% and 60% is sufficient (Gürbüz & Sahin, 2017). In this context, it can be said that the results of current study are consistent with the literature, that there isn’t need-to remove any items according to the EFA results, and that the scale has a strong construct validity.

The two-factor structure present in the original form of the DLI-9 was also validated in the Turkish version. According to the results-of CFA analysis, the factor loadings of all-items were found to be above 0.30 (Karagöz & Bardakçı, 2020; Çapık et al., 2018). During CFA, various fit indices related to the scale are examined, and it is expected that these indices reach a certain level (Brown, 2015; Karagöz & Bardakçı, 2020). The SRMR, RMSEA, TLI, and CFI fit index values of the original form of the scale were found to be within acceptable limits (Noonan et al., 2024). In this study, it was determined that the CMIN/DF, RMSEA, RMR, SRMR, GFI, AGFI, NFI, TLI, and CFI values are within acceptable limits, consistent with the original scale (Brown, 2015; DeVellis, 2017). The CFA results obtained in this study have demonstrated the construct validity of the scale and confirmed that scale is a valid-measurement-tool.

It is recommended that convergent and discriminant validity analyses be conducted to ensure that the scale items, and sub-dimensions can measure targeted concept without interfering with other concepts (Coskun et al., 2024). In the literature, it is emphasized that CR values should be above 0.70, AVE values should be above 0.50, and CR-values should be greater than AVE-values (Tabachnick et al., 2013; Yaslioglu, 2017). The analysis results obtained in this study has revealed that the scale has both convergent and discriminant validity.

Reliability Analyses of the DLI-9

Test-Retest Reliability

It is recommended to evaluate the test-retest reliability and internal consistency for many multi-item scales such as self-report and observational scales (Polit & Beck, 2017). The test-retest coefficient should be high and the scores between the two measurements should not differ (Weir, 2005). In this study, two administrations were conducted with a three-week interval, and a high positive correlation was calculated between the first and second administrations. Additionally, a paired samples t-test was conducted, and the means of the first and second administrations were found to be very close and similar to each other (Karagöz & Bardakçı, 2020; Weir, 2005). In this context, it can be concluded that the measurements made at different times with the DLI-9 are similar and support reliability of scale.

Cronbach’s α-Reliability Coefficient, Item-Analysis

Whether the scale items are consistent with each other and whether they measure the same feature can be evaluated with Cronbach’s α-coefficient. Higher Cronbach’s α-coefficient, the more reliable scale is considered to be (Seçer, 2018; Tavsancil, 2006). In the present study, the Cronbach’s α-coefficient was calculated as 0.847 for the DLI-9, 0.766 for Factor 1, and 0.822 for Factor 2. In a similar manner to this study, the original scale’s Cronbach’s α value was reported as 0.879, with Factor 1 at 0.820 and Factor 2 at 0.872. In addition, the item-total-score, and item-sub-dimension total-score correlation values of all items in this study were above 0.40. A high item-total-score correlation indicates that relevant-item is appropriate for the theoretical construct being measured, and a correlation-coefficient of 0.20 and above is desirable (Karagöz & Bardakçı, 2020; Çokluk et al., 2018). These results supported the high internal consistency of the DLI-9. Accordingly, it can be stated that all the items in the DLI-9 have a homogeneous structure within themselves, similar to the original scale.

In the item discrimination analysis based on the bottom and top 27% groups, it is evaluated whether the scale can accurately distinguish between the situations related to the subject being investigated (Karagöz & Bardakçı, 2020). A significant difference is expected to be found between the bottom and top groups formed according to the total test scores (Büyüköztürk, 2008; Tavşancıl, 2006; Şencan, 2005). In this study, it can be concluded that the items of the DLI-9 have a distinctive feature regarding the subject being investigated.

The Hotelling-T² test, conducted to determine the response bias of scale, examines whether the participants’ responses to the scale-items are equal to each other (Karagöz & Bardakçı, 2020; Özdamar, 2002). In this study, it was concluded that there is no response bias in the DLI-9. The reliability of the DLI-9 was supported by the results obtained from all reliability analyses.

Limitations

The participants were reached using the snowball sampling method. This situation may tend to result from the participation of individuals with higher DL, and data is based on self-reports from participants. The DLI-9 was developed in the Australian community and adapted to the Turkish community; it will need to be tested for use in other communities.

Conclusion

In conclusion, it has been observed that the DLI-9 is a valid, and reliable tool for assessing DL in Turkish society. This tool adapted to Turkish is short and practical for evaluating adults’ DL. The scale will facilitate the evaluation of DL for all professionals working in the fields of health and social sciences.

Footnotes

ORCID iDs

Vahide Semerci Çakmak

Ahmet Seven

Ethical Approval

Before starting the study, approval was obtained from the Bayburt University Non-Interventional Clinical Research Ethics Committee (Decision No: 2024/70/8-Date:10/17/2024).

Informed Consent

Before starting the survey questions in the online form, a written explanation about the study was provided and a question was asked about whether they were willing to participate in the study. Those who agreed to participate in the study answered the survey questions.

Author Contributions: CRediT

Vahide Semerci Çakmak: Conceptualization, Methodology, Software, Supervision, Writing- Reviewing and Editing. Ebru Sönmez Sarı: Data curation, Writing- Original draft preparation, Visualization, Investigation. Ahmet Seven: Software, Validation, Writing- Original draft preparation.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Data Availability Statement

Upon reasonable request, data can be made available to researchers. Requests should be directed to the corresponding author.*

Author Biographies

Vahide Semerci Çakmak completed her PhD in Manisa Celal Bayar University Internal Medicine Nursing. In her doctoral thesis, she examined the issue of rational drug use and health literacy in hypertension patients. She currently works as an Associate Professor at Tokat Gaziosmanpaşa University, Faculty of Health Sciences, Department of Nursing. She works on chronic diseases such as diabetes and hypertension.

Ebru Sönmez Sari completed her PhD in Gazi University Public Health Nursing. She studied the issue of promotion and protection elderly health in her PhD thesis. She is now working as an Associate Professor at Bayburt University, Faculty of Health Sciences, Department of Nursing. She works on promotion and protection public health.

Ahmet Seven is currently working as an Assistant Professor at Kahramanmaras Sütcü Imam University, Faculty of Health Sciences, Department of Nursing. He has specialized in the field of palliative care. He continues his studies in the field of internal medicine nursing.

References

Brown

T. A.

(2015). Confirmatory factor analysis for applied research (2nd ed.). Guilford Publications.

Büyüköztürk

Ş.

(2008). Data analysis handbook for social sciences (9th ed.). Pegem Akademy.

Çam

M. O.

Baysan-Arabaci

(2010). Qualitative and quantitative steps on attitude scale construction. Turkish Journal of Research & Development in Nursing, 12(2), 59–71. https://dergipark.org.tr/tr/pub/hemarge/issue/52709/695121

Çapık

Gözüm

Aksayan

(2018). Intercultural scale adaptation stages, language and culture adaptation: Updated guideline. Florence Nightingale Journal of Nursing, 26(3), 199–210. https://doi.org/10.26650/FNJN397481

Çekiç

Çalişkan

B. B.

Öztürk

G. K.

Meral

D. K.

Bağ

(2024). It was the first time someone had died before my eyes…: A qualitative study on the first death experiences of nursing students. Nurse Education Today, 133(106075), 1–6. https://doi.org/10.1016/j.nedt.2023.106075

Che

S. L.

Zhu

W. I.

(2023). The death literacy index: Translation, cultural adaptation, and validation of the Chinese version. Frontiers in Public Health, 11, 1–13. Article 1140475. https://doi.org/10.3389/fpubh.2023.1140475

Çokluk

Ö.

Şekercioğlu

Büyüköztürk

Ş.

(2018). SPSS and LISREL applications of multivariate statistics. Pegem Akademy.

Coskun

A. B.

Elmaoğlu

Bektaş

(2024). Development and psychometric testing of the pediatric atraumatic care attitude scale (PACAS) in pediatric nurses. Journal of Pediatric Nursing, 79(1), e31–e37. https://doi.org/10.1016/j.pedn.2024.09.015

DeVellis

R. F.

(2017). Scale development: Theory and application (4th ed.). Sage Publications.

10.

Graham-Wisener

Toner

Leonard

Groarke

J. M.

(2022). Psychometric validation of the death literacy index and benchmarking of death literacy level in a representative UK population sample. BMC Palliative Care, 21(1), 145. https://doi.org/10.1186/s12904-022-01032-0

11.

Gürbüz

Sahin

(2017). Research methods in social sciences: Philosophy-method-analysis (4th ed.). Seçkin Publishing.

12.

Johansson

Olsson

Å.

Tishelman

Noonan

Leonard

Eriksson

L. E.

Cohen

(2023). Validation of a culturally adapted swedish-language version of the death literacy index. PLoS One, 18(11), Article e0295141. https://doi.org/10.1371/journal.pone.0295141

13.

Kamiloglu

Vural

P. I.

(2022). The Turkish validity and reliability study of fertility desire. ScaleYOBU Faculty of Health Sciences Journal, 3(1), 1–13. https://dergipark.org.tr/tr/pub/yobusbf/issue/68654/1088828

14.

Karagoz

Bardakci

(2020). Measurement tools and scale development used in scientific research. Nobel Academic Publishing.

15.

Leonard

Noonan

Horsfall

Kelly

Rosenberg

J. P.

Grindrod

Rahn

(2022). Developing a death literacy index. Death Studies, 46(9), 2110–2122. https://doi.org/10.1080/07481187.2021.1894268

16.

Che

S. L.

Zhu

W. I.

(2024). What we learnt from parents’ death experience: A cross-sectional study of death literacy and parent’s death quality among adult children in China. Palliative & Supportive Care, 22(5), 1217–1225. https://doi.org/10.1017/S1478951523001657

17.

Noonan

Grindrod

Shrestha

Lee

Leonard

Johansson

(2024). Progressing the death literacy index: The development of a revised version (DLI-R) and a short format (DLI-9). Palliative Care and Social Practice, 18(1), 1–13. https://doi.org/10.1177/263235242412748

18.

Noonan

Horsfall

Leonard

Rosenberg

(2016). Developing death literacy. Progress in Palliative Care, 24(1), 31–35. https://doi.org/10.1080/09699260.2015.1103498

19.

Özdamar

(2002). Reliability and question analysis. Statistical data analysis with package programs. Etam Inc.

20.

Polit

Beck

(2017). Nursing research: Generating and assessing evidence for nursing practice (10th ed., pp. 446–447). Lippincott Williams & Wilkins.

21.

Polit

D. F.

Beck

C. T.

(2006). The content validity index: Are you sure you know what's being reported? Critique and recommendations. Research in Nursing & Health, 29(5), 489–497. https://doi.org/10.1002/nur.20147

22.

Seçer

(2018). Psychological test development and adaptation process; spss and lisrel applications (2nd ed.). Ani Publishing.

23.

Semerci

Sönmez Sari

Seven

(2024). Validity and reliability of the Turkish version of the death literacy index. Omega, 88(3), 807–822. https://doi.org/10.1177/00302228221144672

24.

Şencan

(2005). Reliability validity in social and behavioral measures. Seçkin Publishing.

25.

Serra-Sutton

Fernández-Giner

Espallargues

García-Altès

Good death study in Catalonia . (2024). Defining a good death: Perspectives of patients, relatives, and health care professionals in the Catalan context-A qualitative study. PLoS One, 19(11), Article e0312426. https://doi.org/10.1016/j.nedt.2023.106075

26.

Tabachnick

B. G.

Fidell

L. S.

Ullman

J. B.

(2013). Using multivariate statistics (pp. 497–516). Pearson.

27.

Tavsancil

E. T.

(2006). Measuring attitudes and data analysis with SPSS (3th ed.). Nobel Publications.

28.

Van Dinther

Noonan

Leonard

Javanparast

(2025). The death literacy index: Testing the death system literacy of unpaid carers of palliative patients. Omega, 0(0), 00302228251319478. https://doi.org/10.1177/00302228251319478

29.

Weir

J. P.

(2005). Quantifying test-retest reliability using the intraclass correlation coefficient and the SEM. The Journal of Strength & Conditioning Research, 19(1), 231–240. https://doi.org/10.1519/15184.1

30.

Wild

Grove

Martin

Eremenco

McElroy

Verjee-Lorenz

Erikson

ISPOR Task Force for Translation and Cultural Adaptation . (2005). Principles of good practice for the translation and cultural adaptation process for patient-reported outcomes (PRO) measures: Report of the ISPOR task force for translation and cultural adaptation. Value in Health: The Journal of the International Society for Pharmacoeconomics and Outcomes Research, 8(2), 94–104. https://doi.org/10.1111/j.1524-4733.2005.04054.x

31.

Yaslioglu

M. M.

(2017). Factor analysis and validity in social sciences: Application of exploratory and confirmatory factor analyses. Istanbul Business Research, 46(1), 74–85. https://dergipark.ulakbim.gov.tr/iuisletme