Introduction
Subjective aging refers to how people think about their growth and aging during adulthood and old age and covers concepts that try to understand the ways in which people experience the aging process [5]. That is, apart from chronological age as an indicator of their age in life, people interpret their behavioral experiences in the aging process to create a feeling of subjective aging [6], and this feeling becomes an important part of self and identity of elderly people [7]. Age stereotypes, as one of the concepts of subjective aging, are common social beliefs about the aging process and elderly people, which can have significant effects on the physical and mental health of the elderly [27]. The current study aims to assess psychometric properties of the Persian version of the age stereotypes questionnaire.

Methods
This is descriptive-cross-sectional study. Participants were 360 elderly people in Kermanshah, Iran in 2022, who were selected using a convenience sampling method and based on the inclusion criteria, which were at least 60 years old, the ability to communicate and complete the questionnaire, and consent to participate in the study. The questionnaire was first translated into Persian accordance with the standard protocol of the World Health Organization (WHO) and using the back-translation method. Then, its face validity and content validity were evaluated. Confirmatory factor analysis was used to determine its construct validity. The fit indices (CMIN, df, CMIN/df, CFI, NFI, SRMR, RMSEA) were used to assess the fitness of the model. Internal consistency of the overall scale was assessed using Cronbach’s alpha, and McDonald’s omega was used for each subscale. In addition, composite reliability and average variance extracted (AVE) were measured. To determine the concurrent validity, the questionnaire of awareness of age-related changes (AARC) was used. Statistical analyses were performed in SPSS software, version 26 and AMOS software, version 24.

Results
In this study, 48.6% (n=175) of respondents were male, and 51.4% (n=185) were female. Their mean chronological age was 67.66 years, ranging from 60 to 91 years. In evaluating the face validity and content validity of the questionnaire, it was given to 5 faculty professors, who all expressed their positive opinions about the content and form of this questionnaire after applying some amendments to the items. Based on the construct validity test results (CMIN=708.520, df=296, CMIN/df=2.39, CFI=0.94, NFI=0.91, SRMR=0.032, RMSEA=0.062), the model had a good fit. Cronbach’s alpha coefficient for family and partnership subscale was 0.871; for the friends and acquaintances subscale, 0.842; for religion and spirituality subscale, 0.747; for leisure activities and social or civic commitment subscale, 0.774; for personality and way of living subscale, 0.809; for financial situation and dealing with money-related issues, 0.846; for work and employment subscale, 0.859; and for physical and mental fitness, health and appearance, 0.874. Also, the factor loads calculated for all the items were above 0.5, and all were found to be statically significant (P≤0.05). Also, all the value of the AVE was greater than 0.5 and the composite reliability coefficient was greater than the AVE; thus, the reliability of the measurement model was acceptable. The results of the concurrent validity test showed that all subscales of the age stereotypes questionnaire had a significant relationship with the gains and losses subscales of the AARC questionnaire, mostly with the gains subscale. Therefore, the scale had good concurrent validity.

Conclusion
The Persian version of the age stereotypes questionnaire has good validity and reliability. It has low number of items and requires a short time to complete. Therefore, it can be used to investigate and evaluate positive and negative age stereotypes in Iran.

Ethical Considerations
Compliance with ethical guidelines
This study has ethical approval from Razi University Code: 2867643 ). All procedures were in accordance with the ethical guidelines of the research committee and the 1964 Declaration of Helsinki. A written informed consent was obtained from all participants, and they were assured of the confidentiality of their information.

Funding
This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

Authors' contributions
The authors contributed equally to preparing this article.

Conflicts of interest
The authors declare no conflict of interest.

Acknowledgments
The authors would like to thank all the seniors participated in this study for their cooperation.

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