RESUMEN
BACKGROUND: The quality of the parent-child relationship has an important effect on a wide range of child outcomes. The evaluation of interventions to promote healthy parenting and family relationships is dependent on outcome measures which can quantify the quality of parent-child relationships. Between the Mothers' Object Relations - Short Form (MORS-SF) scale for babies and the Child-parent Relationship Scale (C-PRS) there is an age gap where no validated scales are available. We report the development and testing of an adaptation of the MORS-SF; the MORS (Child) scale and its use in children from the age of 2 years to 4 years. This scale aims to capture the nature of the parent-child relationship in a form which is short enough to be used in population surveys and intervention evaluations. METHODS: Construct and criterion validity, item salience and internal consistency were assessed in a sample of 166 parents of children aged 2-4 years old and compared with that of the C-PRS. The performance of the MORS (Child) as part of a composite measure with the HOME inventory was compared with that of the C-PRS using data collected in a randomised controlled trial and the national evaluation of Sure Start. RESULTS: MORS (Child) performed well in children aged 2-4 with high construct and criterion validity, item salience and internal consistency. One item in the C-PRS failed to load on either subscale and parents found this scale slightly more difficult to complete than the MORS (Child). The two measures performed very similarly in a factor analysis with the HOME inventory producing almost identical loadings. CONCLUSIONS: Adapting the MORS-SF for children aged 2-4 years old produces a scale to assess parent-child relationships that is easy to use and outperforms the more commonly used C-PRS in several respects.