I am trying to find an instrument that can be completed by primary caregivers and children in middle childhood that assesses emotional closeness in the relationship. Any suggestions?
I have a few that I like in terms of measuring different aspects of the relationship between children/teens and primary caregivers. The Parenting Stress Index (or for children in an older age bracket the Stress Index for Parents of Adolescents) and the Parent Child Relationship look at parents perception of the parent about the child specifically looking at the degree of attachment, degree to which the parent feels reinforced by interactions, etc...
Another assessment I find useful is the Family Assessment Measure III (FAM-III). It has three different forms (1) the general assessment of the family (2) the assessment of how an individual feels that are performing within the family, and (3) the dyadic form, which measures how an individual looks at their relationship between another family member. Both adults and pre-teens/teens can fill this out, which makes it easy to see the differences in perception of the relationship.
another option might be the EMBU - we have used it for German and Turkish immigrant children's self-report from 8-15 years of age (results not published yet) and it works well.
You might also want to examine the Emotional Availability Scales. It sounds as though this might be in line with what you are trying to examine. Good luck!