This Alberta Official Statistic compares the family size of Canadian Census families in all provinces and territories for the 2011 Census year. A census family refers to a married couple (with or without children of either and/or both spouses), a common-law couple (with or without children of either and/or both partners) or a lone parent of any marital status, with at least one child. A couple may be of opposite sex or same sex. A couple family with children may be further classified as either an intact family in which all children are the biological and/or adopted children of both married spouses or of both common-law partners or a stepfamily with at least one biological or adopted child of only one married spouse or common-law partner and whose birth or adoption preceded the current relationship. Stepfamilies, in turn may be classified as simple or complex. A simple stepfamily is a couple family in which all children are biological or adopted children of one, and only one, married spouse or common-law partner whose birth or adoption preceded the current relationship. A complex stepfamily is a couple family which contains at least one biological or adopted child whose birth or adoption preceded the current relationship.