Development of a Short Form of the Marital Boundaries Questionnaire Based on Islamic Sources and Examination of Its Psychometric Properties

Extended Abstract
This study aimed to develop a short form of the Marital Boundaries Questionnaire (MBQ) based on Islamic sources and to examine its psychometric properties. The original MBQ, designed by Houshyari (2020), consisted of 66 items. The present research sought to produce a shorter version while maintaining validity and reliability.
The population included 542 married men and women from Qom, selected via convenience sampling. Inclusion criteria were informed consent, no use of psychological services in the past two months and at least two years of marital cohabitation. Marital boundaries refer to Islamic mandatory and non-mandatory teachings regarding spousal relationships, defining the scope of interaction between partners.
Methodology: This research employed a non-experimental, cross-sectional psychometric approach. To reduce items, confirmatory factor analysis (CFA) and inter-item correlations were used. Items with factor loadings below 0.3 or high correlations with other items—considering theoretical and content validity—were removed.
Reliability was assessed using Cronbach’s alpha, and validity through correlation with the original form and CFA. Agreement between the original and short forms in classifying respondents was evaluated using the kappa coefficient.
A sample of 542 participants was considered appropriate, as a sample size of around 500 is “very good” for factor analysis (Houman, 2012). The original MBQ measured six subcomponents:

Marital-specific commitment
Sexual interaction boundaries
Non-sexual interaction boundaries
Exclusive psycho-physical space
Marital-family confidentiality
Reciprocal expectations

The data analysis proceeded in two stages:

Inter-item correlations were examined; items with acceptable psychometric properties were retained.
Factor loadings were considered to select items with the highest loadings per component, using a cutoff of 0.3. Items below this threshold were removed.

Results: The final short form included 35 items and five main components:

Marital-specific commitment (4 items)
Sexual interaction boundaries (5 items)
Non-sexual interaction boundaries (14 items)
Marital-family confidentiality (6 items)
Exclusive psycho-physical space (6 items)

Reliability: Cronbach’s alpha for the total questionnaire was 0.89, and for subcomponents ranged from 0.72 to 0.83, indicating good internal consistency comparable to the original form.
Validity: Correlation between scores of the short and original forms was 0.96 for the total score, and 0.90–0.95 for the subcomponents. The kappa coefficient for classification agreement was 0.79 for the total score and 0.75–0.83 for the subcomponents, demonstrating high concordance between forms.
Discussion and Conclusion: The short form of the Marital Boundaries Questionnaire (MBQ), consisting of 35 items, demonstrates satisfactory validity and reliability and can serve as an effective tool in family-related research within Islamic societies. Reducing the number of items without compromising content or construct validity allows for quicker and broader administration. Moreover, the merging of the “reciprocal expectations” component with the “non-sexual interaction boundaries” component due to conceptual overlap was one of the key findings of this study.
The statistical analysis combined with theoretical considerations resulted in a 35-item questionnaire measuring five components: marital-specific commitment, sexual interaction boundaries, non-sexual interaction boundaries, marital-family confidentiality, and exclusive psycho-physical space. The correlation between the short and original forms was 0.96, indicating that the short form explains approximately 92% of the variance in responses compared to the original questionnaire.
The primary reason for item reduction was the presence of several items with overlapping content. During the development of the original questionnaire, the researcher included multiple items with different phrasings for each indicator to ensure that if any items were later removed during validity, reliability, or standardization processes, the content validity of the questionnaire would remain intact. In creating the short form, the best-performing items with the highest factor loadings were selected.
The process also revealed that items from the “reciprocal expectations” component were conceptually very similar to items in the “non-sexual interaction boundaries” component. Statistical analyses confirmed this overlap, so the items from these two components were combined under the “non-sexual interaction boundaries” label.
In the original MBQ, reciprocal expectations refer to spouses’ interactions and mutual expectations regarding their rights and responsibilities, including male management and supervision, acceptance of male authority and management by the wife, adherence to qualitative family management standards by the husband, economic cooperation between spouses, shared spiritual and religious space, and protection of each other’s reputation and property. Although independent attention to reciprocal expectations has significant effects on family interactions, given the nature of these interactions, they can also be considered a specific type of non-sexual interaction.
Non-sexual interaction boundaries in the original questionnaire include all non-mandatory moral rules and etiquettes of spousal interactions, which in the Qur’an are referred to as “mo‘asherat ma‘ruf” (appropriate interaction) in times of agreement and “imsak bi ma‘ruf” or “separation bi ma‘ruf wa ihsan” in case of marital conflicts. Examples include respecting the spouse’s family, fulfilling emotional needs, verbal expressions of affection, greeting and farewelling each other, politeness, overlooking minor faults, gift-giving, and cooperation in religious and worldly affairs. These represent ethical marital boundaries.
The short form of the MBQ retains all the main features of the original questionnaire, including a precise theoretical foundation based on Islamic teachings, as well as satisfactory validity and reliability. Due to its reduced number of items and focus on those with the highest factor loadings, it offers improved practical applicability and efficiency for research purposes.