What are the principles in custody when the issue is not custody but rather primary residence?

To what degree, then, is discussion of principles in custody cases applicable where the issue is not custody but rather primary residence? Custody, access and guardianship are concepts known to the law and used in legislation. “Primary residence”, on the other hand, is not a defined term. Rather it is a term that connotes an aspect of custody, but without all the attendant legal authority over the child. Arrangements for care of a child have many models; aspects of child responsibility and child care are capable of being organized into a variety of sub-sets of the two large and legally meaningful categories of custody and guardianship. “Primary residence” is a sub-set of custody, so to speak, falling short of the full legal responsibility inherent in that term. As a vital aspect of parental care for a child, however, it seems. to me only right that the same considerations should apply to a decision on primary residence as apply to custody questions. I consider that in circumstances of a parent who is and has been the primary caregiver, and provides the primary residence for the child, the Gordon v. Goertz instruction to respect the views of the mobile parent, applies fully.