<xsd:element name="ProviderId" minOccurs="0">
    <xsd:complexType>
        <xsd:simpleContent>
            <xsd:extension base="xsd:string">
                <xsd:attribute name="providerIdQualifier" use="required">
                    <xsd:simpleType>
                        <xsd:restriction base="xsd:string">
                            <xsd:enumeration value="Social Security Number" />
                            <xsd:enumeration value="Federal Taxpayer Identification Number" />
                            <xsd:enumeration value="HCFA National Provider Identifier" />
                            <xsd:enumeration value="Mutually Defined" />
                        </xsd:restriction>
                    </xsd:simpleType>
                </xsd:attribute>
            </xsd:extension>
        </xsd:simpleContent>
    </xsd:complexType>
</xsd:element>