Resident status determination clarifies tie breaker rules for dual residence and place of effective management resolution. Residence is defined by liability to tax under domestic law and excludes persons taxable only on source income. Dual residence for individuals is resolved by successive tie breaker tests: permanent home, centre of vital interests, habitual abode, nationality, and, if unresolved, mutual agreement between competent authorities. For juridical persons, residence is determined by the place of effective management, with unresolved cases referred to mutual agreement between the competent authorities.