Development and psychometric evaluation of the questionnaire on the contributing factors of tendency towards voluntary single-childedness and childlessness: a mixed method study.

Couples' tendency towards voluntary single-childedness and childlessness (VSCC) has turned into a major challenge in all societies and led to different problems such as population aging. A key step to VSCC management is to determine its contributing factors through valid and reliable instruments. This exploratory sequential mixed method study (qualitative-quantitative) was conducted in 2020-2021. Phases of qualitative consists of all couples aged 15-49 in Babol, Iran, who were single or childless. Sampling is based on the purpose, and the number of samples is 20 couples. To collect data, face-to-face and semi-structured interviews were conducted with the participants. Sampling continued until data saturation. The data were analyzed by the conventional content analysis method and quantitative phase. Initially, a qualitative study was conducted on twenty couples, and were analyzed through conventional content analysis. Findings were used to develop QFT-VSCC and then, the face, content, and construct validity as well as reliability were assessed. Construct validity was assessed through exploratory and confirmatory factor analyses and reliability was assessed through internal consistency and stability assessments. The results of the qualitative part analysis consist of 140 codes, 30 primary categories, and nine main categories and two themes (individual limitations and social limitations). The primary QFT-VSCC had 78 items. Fifty-eight items were omitted during validity assessment and the remaining twenty-two items were loaded on five factors during factor analysis. These factors were threatened priorities, inappropriate familial context for childbearing, sense of occupational and social insecurity for the child, social modeling of childlessness, and tendency towards change or stability in marital life. The five factors explained 52.56% of the total variance. All model fit indices in confirmatory factor analysis were acceptable and the Cronbach's alpha values of QFT-VSCC and all its factors were more than 0.70. The results of convergent validity analysis revealed that all factors had an AVE value greater than 0.5, and the HTMT index for all factors was less than 0.85. This indicated that discriminant validity had been achieved. QFT-VSCC is a simple valid and reliable instrument for VSCC assessment among both men and women.