Scientists Translate and Validate a Sexual Motivation Scale for Iranian Married Adults

Sexual motivation sits at the heart of intimate relationships, shaping desire, satisfaction, and long-term partnership stability, yet measuring it reliably across cultures has always been a stubborn challenge. A research team in Iran has now taken a major step toward closing that gap. In a methodological study published in BMC Psychology, Maryam Salari of Qaem Hospital at Mashhad University of Medical Sciences and her colleagues report the psychometric evaluation of a Persian version of the Sexual Motivation Scale, or SexMS, among Iranian married men and women. Their findings suggest that the translated instrument holds up remarkably well, offering clinicians and researchers in Persian-speaking populations a validated tool for exploring one of the most private dimensions of human motivation.

The original Sexual Motivation Scale was developed by Gravel and colleagues in 2016 and is grounded in self-determination theory, one of the most influential frameworks in contemporary motivational psychology. Rather than treating sexual motivation as a single dial that runs from low to high, the scale maps it onto a multidimensional continuum. At one end lies amotivation, the absence of any drive toward sexual activity. Moving along the continuum, motivation can be external, driven by outside pressures or rewards; introjected, fueled by internal guilt or self-imposed expectations; identified, reflecting personally valued goals; integrated, where sexual behavior harmonizes with one’s core sense of self; and finally intrinsic, where the activity is pursued for its own inherent pleasure and satisfaction. This architecture allows researchers to ask not simply how motivated someone is, but why.

Translating a psychologically sensitive instrument is far more mechanical than running text through a dictionary, and the Iranian team followed a rigorous standardized forward-backward protocol. Bilingual translators independently rendered the original 24 items into Persian, and a separate set of translators, blind to the original wording, translated the Persian version back into English. Discrepancies between the back-translation and the source items were examined and reconciled, a process designed to catch subtle shifts in meaning that could distort what respondents actually answer. For a scale touching on sexuality in a culturally conservative context, preserving nuance is not a technical nicety but an absolute requirement for valid measurement.

Before any participant filled in a questionnaire, the translated items faced a panel of experts who judged their relevance and clarity using two established metrics: the content validity ratio, or CVR, and the content validity index, or CVI. Both indices quantify how strongly a panel agrees that each item is essential and representative of the construct it is meant to capture. The Persian SexMS performed well on both counts, achieving a CVI of 0.87 and a CVR of 0.89, figures that indicate satisfactory agreement among the expert reviewers and cleared the instrument for field testing.

The field test itself involved 394 married adults aged 18 to 60, recruited from health centers in Mashhad, a major city in northeastern Iran. Participants completed a demographic questionnaire alongside the Persian SexMS. Given the sensitive nature of the subject matter, the researchers implemented unusually careful privacy protocols. Respondents filled out the questionnaires alone in dedicated consultation rooms separated from routine clinical areas, ensuring both visual and auditory privacy. No names or contact details were collected; each form carried only a numerical identification code. Completed questionnaires went directly from participants into sealed, opaque collection boxes that healthcare center staff could not access, and participants were told explicitly that joining or withdrawing would have no effect on the care they received. These safeguards were designed to suppress social desirability bias, the well-documented tendency of people to answer sensitive questions in ways that make them look good.

The statistical centerpiece of the study was confirmatory factor analysis, or CFA, a technique that tests whether the pattern of responses actually matches the theoretical structure the scale claims to have, in this case six correlated factors corresponding to the six motivational types. The initial analysis flagged a problem: item 4, belonging to the intrinsic motivation subscale, showed a factor loading below the conventional 0.30 threshold, meaning it correlated too weakly with its intended factor to carry its weight. The researchers removed it and re-ran the analysis on the remaining 23 items. The re-specified model fit the data acceptably, with a chi-square to degrees-of-freedom ratio of 2.83, a comparative fit index of 0.90, an incremental fit index of 0.90, and a root mean square error of approximation of 0.068 with a 90 percent confidence interval of 0.061 to 0.076. In plain terms, the six-factor architecture of the original scale survived translation largely intact.

Reliability, the question of whether the instrument produces consistent measurements, was assessed in two complementary ways. Internal consistency examines whether items within each subscale correlate with one another as they should, and the Persian SexMS delivered a Cronbach’s alpha of 0.868 and a McDonald’s omega of 0.882, both comfortably within the range considered good for a multidimensional psychological scale. Test-retest stability was evaluated by asking participants to complete the scale a second time two weeks later, and the intraclass correlation coefficient came in at 0.87, a strong figure indicating that scores were highly stable over an interval long enough to filter out momentary mood swings but short enough that genuine motivation was unlikely to have shifted.

Beyond the headline statistics, the subscale scores offer an intriguing glimpse into the motivational profile of the sample. Integrated regulation, the form of motivation in which sexual behavior is experienced as fully congruent with one’s values and identity, yielded the highest mean score at 21.49 with a standard deviation of 5.44. Amotivation, the near-absence of any drive, scored lowest at 7.14 with a standard deviation of 4.74. The pattern is consistent with self-determination theory’s prediction that among well-functioning married adults, autonomous and self-endorsed forms of motivation tend to dominate over pressured or absent ones, though the authors present these as descriptive findings for the sample rather than population-level claims.

The practical implications extend well beyond academic curiosity. Sexual motivation is closely tied to sexual health, relationship satisfaction, and the assessment of conditions ranging from hypoactive desire to the psychological side effects of medical treatments. Until now, Persian-speaking clinicians and researchers lacked a validated multidimensional measure of this construct, forcing them to rely on unvalidated translations or single-item questions that collapse a rich motivational landscape into a crude summary. A psychometrically sound 23-item Persian SexMS opens the door to studies tracking how motivation profiles differ across age groups, marital durations, and clinical populations, and gives counselors a structured way to explore why a client’s desire has changed rather than merely how much.

The study, funded by Mashhad University of Medical Sciences as part of a master’s thesis, also stands as a case study in how careful measurement science works. Every step, from forward-backward translation to expert panel review, privacy-protected data collection, confirmatory factor analysis, and dual reliability testing, reflects the methodological discipline required before a questionnaire can be trusted. The authors caution that their validation applies to married Iranian adults recruited from health centers in one city, and further work in other regions and populations would strengthen generalizability. Still, the core message is clear: a decade after the original SexMS appeared, its theoretical backbone has now been shown to travel across languages and cultures, giving researchers in Iran and potentially the wider Persian-speaking world a rigorous instrument for investigating the motivations that animate one of the most intimate corners of human life.

Subject of Research: Psychometric validation of the Persian Sexual Motivation Scale in Iranian married adults

Article Title: Psychometric evaluation of the Persian version of the sexual motivation scale (SexMS) in Iranian married men and women

Article References: Salari, M., Abdollahpour, S., Jafari, A., & Moradi, M. (2026). Psychometric evaluation of the Persian version of the sexual motivation scale (SexMS) in Iranian married men and women. BMC Psychology. https://doi.org/10.1186/s40359-026-05728-3

Image Credits: AI Generated

DOI: 10.1186/s40359-026-05728-3

Keywords: sexual motivation, SexMS, psychometrics, self-determination theory, Persian translation, confirmatory factor analysis, reliability, validity, Iranian married adults, sexual health, BMC Psychology, questionnaire validation