Inter-Level Codes
Municipality Identifier
The Municipality Identifier is the core of the national standard geographic classification system. This is composed of the Province Code followed by the Municipality Code. The Municipality Identifier is a four-digit number that defines the identity of the municipality.
Illustration:
The municipality Identifier 7310. The first two-digits 73 is the Province Code for the province of Zamboanga del Sur. The last two-digits 10 is the Municipality Code. This means that it is the 10th municipality within the province of Zamboanga del Sur, which in this instance is Kabasalan. The Municipality Identifier 7310 would therefore define Kabasalan, Zamboanga del Sur.
Continuous addition of newly created barangays as a result of periodic updating resulted in the discontinuous alphabetic arrangement of barangays in the later portion of the list.
Municipality Code Dependent on Province Code
It will be noted from the above illustration that the Municipality Code only provides for the relative alphabetical sequence of the municipality within the province (e.g. 1st, 2nd, 3rd, etc.). By itself it is not sufficient to define the municipality. However, when the same is attached to the Province Code, it acquires a unique meaning. For the Municipality Identifier 7310, there is only one municipality within Zamboanga del Sur whose code is 10, and this is the municipality of Kabasalan. Hence, the Municipality Identifier (Province Code and Municipality Code) defines the unique identity of the Municipality.
Municipality Identifier Independent of Region Code
As has been pointed out, the Municipality Identifier not only identifies the municipality but also the province to which it belongs. An added feature of the Municipality Identifier is its independence from the Region Code. Regardless of the Region, the Municipality Identifier for Kabasalan will remain 7310 as long as it is part of Zamboanga del Sur.
Barangay Identifier
Illustration:
Barangay Identifier 7310001. The first four digits 7310 is the Municipality Identifier as fully explained in section 4.2. The last three digits 001 is the Barangay Code which refers to the first barangay within the municipality with Municipality Identifier 7310. Barangay Code 001, in this case, refers to Barangay Balongis. Thus, Barangay Identifier 7310001 means Barangay Balongis in Kabasalan, Zamboanga del Sur.
Barangay Code Dependent on Municipality Identifier. The Barangay Code only provides for the relative alphabetical sequence of the barangays in the municipality. Barangay Code 001 means it is the first barangay in the alphabetical sequence. By itself the Barangay Code is not sufficient to define the identity of the barangay. However, when the Barangay Code is attached to a Municipality Identifier, the result is a unique code which fully establishes the identity of the barangay. In Barangay Identifier 7310001 there is only one barangay in the entire Philippines with such code number, and that is Barangay Balongis in Kabasalan, Zamboanga del Sur.
Hierarchy of Recapitulation
(09) - 7310-001 : Barangay Identifier, with Region Code prefixed. This gives the details on the barangay level. By definition, the aggregate of all barangays in a municipality defines the municipality.
(09) - 7310 : Municipality Identifier, with Region Code prefixed. This gives the details on the municipality level. The aggregate of all municipalities defines the province.
0973 : Region and Province Code. This is the recapitulation of details by province, within each region.
Agency Unique Requirement
The Philippine Standard Geographic Code establishes standardization for the following: Region, Province, Municipality and Barangay. This however, does not preclude an agency from devising additional sub-categorization on geographic area units geared purely to its operational functions to meet its unique requirements.
A good case in point here is the unique requirement of National Statistics Office (NSO) in statistical surveying functions. In addition to the Region, Province, Municipality and Barangay Code, it needs additional coding for the Enumeration District (ED) as well as rural and urban classification. This is purely a unique requirement of the NSO to monitor and enhance its survey operations. Other agencies may have similar unique requirements.
In order to effect standardization and at the same time be responsive to the unique operational requirements of an agency, the following guidance was established:

Source: www.nscb.gov.ph