Technical Notes:

The compilation of the Food Balance Sheet requires basic data on production, stocks, foreign trade, domestic utilization, nutrient values, dietary allowances and population which were obtained from the results of censuses, household and establishment surveys, administrative reports of government agencies and special studies conducted by various research institutions.
1. Production
1.1 Food Crops
The production data of palay and corn were obtained from the quarterly Palay and Corn Production Survey of the BAS. Except sugarcane and coconut, production data for other crops such as roots and tubers, pulses and nuts, vegetables and fruits were generated through a rider to the BAS Palay and Corn Production Survey. These data were supplemented with the data from BAS quarterly monitoring of major producing provinces through the conduct of field interviews of key farmers and ocular inspection in the area.
The Sugar Regulatory Administration (SRA) provided data on centrifugal sugar based on the monthly reports of sugar centrals, while the BAS provided production data in terms of panocha and muscovado. Both data sets were used to estimate the production of sugarcane products using the available parameters. On the other hand, the Philippine Coconut Authority provided data on coconut production in terms of copra based on the monthly reports of its provincial field offices. For food crops not included in the BAS surveys, production was estimated using parameters based on the results of the 1991 Census of Agriculture and Fisheries conducted by the National Statistics Office (NSO).
1.2 Livestock and Poultry Including Milk and Eggs
For livestock and poultry animals, production data including the production of milk and eggs were taken from the BAS Survey of Backyard Livestock and Poultry Farms (BLPS) and Survey of Commercial Livestock and Poultry Farms(CLPS). Data used include the inventory of animals and production of milk and eggs which were disaggregated for all types of animals such as carabao, cattle, hogs, goat, chicken and ducks. For other animals not covered by BAS surveys, estimates of production including milk and egg production were obtained using parameters derived from the 1991 Census of Agriculture and Fisheries.
1.3 Fish and Other Marine Products
For fish and other marine products, production data were sourced from the quarterly fishery surveys of the BAS such as the Survey of Commercial Fish Landing Centers, Survey of Municipal Fish Landing Centers, and Survey of Aquaculture Farms. The above surveys provided data on total fish production including the production of other marine products such as crustaceans, mollusks, and other seafoods like seaweeds, sea urchins, etc.
1.4 Processed Food Commodities
The Census of Establishments (CE) and the Annual Survey of Establishments (ASE) were the primary sources of data for processed food commodities such as wheat flour, cassava flour and starch, processed vegetables, processed fruits, fats and oil and other miscellaneous foods. The 1988 and 1994 CE provided the baseline data while the ASE provided the annual data to estimate production. The data used from the CE/ASE include value of products sold and the value of inventory for each commodity. To derive the volume of production, the producer's price of each commodity from the Monthly Producer's Price Survey of the NSO were used.
For some food commodities such as rice, corn grits and other food preparations, other data sources include the University of the Philippines Los Baños (UPLB), Food and Nutrition Research Institute (FNRI) and the Department of Science and Technology (DOST).
2. Stocks
Stock data on palay, rice and corn were obtained from the Palay and Corn Household Stock Survey of the BAS and from the regular monitoring system of commercial and government stocks of the National Food Authority (NFA).
3. Foreign Trade
Data on the volume of merchandise exports and imports of each food commodity were obtained from the Foreign Trade Statistics compiled by the NSO. These data were from customs manifests, a document being accomplished by exporters and importers as a requirement of the Bureau of Customs for clearance.
4. Domestic Utilization
Data on domestic utilization such as feeds, seeds, waste, processed for food and non-food were obtained using parameters from special surveys and studies conducted by the BAS, other research institutions such as the UPLB, FNRI and DOST. The Input-Output Survey of Establishments of the NSO (Annex 1) also provided other data inputs.
5. Nutrient Values
The nutrient values in terms of energy, protein and fats for each food item measured per 100 grams in retail weight of "as purchased basis (Annex 2)" were obtained from the 1987 Food Composition Tables on Mean One-Day Capita Food Intake generated by the FNRI (Annex 2).
6. Recommended Dietary Allowance
The FNRI through its Food Consumption Survey provided the recommended dietary allowance disaggregated by food commodity and by major food group.
7. Population
The mid-year population estimates of the Households Statistics Department of the NSO based on the 1990 Census of Population and Housing (CPH) were used for the estimation of the per capita food supply and the per capita food nutrient to make it comparable with the previous years' estimates. The population data from the 1995 Census of Population will be reflected in the next publication in time for the plan to revise the link series that will cover the years 1992 to 1999.
1. Total Domestic Supply (TDS)
TDS = Production - Changes in Stocks + Net Imports
This represents the quantity of food supplies available before disposal to non-food and food uses. It is obtained by adding the change in stocks, if the sign is minus and subtracting it, if the sign is plus, from production, plus net imports (i.e. imports less exports).
1.1 Production
1.1.1. Unprocessed Food Commodities
a) From BAS surveys
The BAS production estimates of unprocessed food commodities such as palay, corn, roots and tubers, vegetables and fruits, livestock and poultry including milk and egg production, fish and marine products were used.
For other pulses and nuts, the production estimate were derived using the trends of local production, imports and exports of commodities under pulses and nuts.
b) From NSO's Census of Agriculture and Fisheries
The 1991 Census of Agriculture and Fisheries (CAF) of the NSO provided the baseline data for the adjustment of the BAS data on organ meat and edible offals to account for other meat and products. The CAF provided data on the number of horse and other livestock to which a ratio was applied to derive the meat equivalent. The ratio was based on the study of BAS and BAI.
1.1.2. Processed Food Commodities
Production estimates of the following processed food commodities were derived by applying appropriate parameters taken from special studies:
a) rice production was estimated by applying a milling recovery rate of 65.4 percent to the total palay production after deducting the estimated amount for seed, feed and waste;
b) corn grits production was estimated by applying a milling recovery rate of 68 percent to the total corn shelled production after deducting allowances for seed, feed, wastage and manufacture for food and non-food;
c) cassava starch production was arrived at by applying an extraction ratio of 20 percent to the total cassava production used for non-food purposes;
d) shelled peanut production was estimated by applying a 70 percent extraction rate to the total unshelled peanut production;
e) processed vegetables and fruits in forms such as canned, dried, juice including other type of food preparations, production estimates were arrived at using the available CE/ASE data on the value of products sold plus the value of the change in inventory, divided by the corresponding price per unit;
f) for livestock and poultry meat production, a dressing percentage which vary by type of animal, was applied to the total number of animals slaughtered. The estimates of total weight of extremities and internal organs of animals such as head, feet and tail, intestines, blood, liver, heart, etc. were estimated based on results of special studies from UPLB and BAI (Annex 4); and
g) for fats, oil, and miscellaneous food commodities, production was estimated by getting the average of the value of output derived using the regression analysis, geometric growth rate and simple average growth rates based on the value of output culled from the CE/ASE publication of the NSO. The estimated value of output for each commodity was deflated using the corresponding producer's price also from the NSO.
1.2 Changes in Stocks
Changes in Stocks = Ending Stocks - Beginning Stocks
The estimates of stocks were carried out for selected commodities to the extent that data are available. This FBS compilation covered estimates of stocks for rice, corn and centrifugal sugar. These estimates served as an adjustment to the reported estimates of total production.
1.3 Net Imports
Net Imports = Total Imports - Total Exports
Data on exports and imports of commodities in terms of quantity (in net kilo equivalent) were sourced from the foreign trade statistics of the NSO. Data for these commodities were aggregated by major food group following the FBS classification. Appropriate conversion factors were then applied to ensure that commodities exported and/or imported are consistently parallel with the production data. Net imports were estimated by deducting from the total imports the total exports of each commodity.
2. Total Domestic Utilization (TDU)
TDU = net available food supply + non-food utilization + processed for food
The net available food supply represents the total amount of food available for consumption while non-food utilization refers to a part of total domestic utilization which is used for seed, feed, processed for non-food including the amount wasted.
2.1 Net Available Food Supply
The net available food supply was obtained by deducting from the total domestic supply of food commodities the total amount for allowances for non-food utilization and processed for food. The amount derived represents the actual quantity of food in the retail stage or "as purchased basis".
2.2 Non-Food Utilization
Estimates of non-food utilization such as seed, feed, processed for non-food and waste made use of parameters available from BAS, UPLB, NSO, FNRI and DOST. These were separately estimated as follows:
2.2.1 feed, which refers to the amount of food for animals, was estimated by applying appropriate parameters to the reported total production of certain food crops;
2.2.2 seed, which refers to the quantity of food crops used as seeds or planting materials, was estimated by applying the recommended seeding allowance per hectare by type of crop;
2.2.3 processed for non-food, which refers to the quantity of food crops converted into non-food commodities for industrial and manufacturing purposes were estimated using the available parameters as shown in Annex 1; and
2.2.4 waste, which refers to the amount of losses that occur during harvesting, infestations, spoilage, storage, distribution, etc., was estimated by applying the required wastage parameters to the total estimate of production or total domestic supply.
2.3 Processed for Food refers to the quantity of food crops which are further processed into other form of food commodities.
3. Per Capita Food Supply
3.1 Annual Per Capita Food Supply (in kilograms)
The annual per capita food supply in kilograms was estimated by dividing the net available food supply by the estimated mid-year population multiplied by 1,000.
3.2 Daily Per Capita Food Supply (in grams)
The daily per capita food supply in grams was estimated by dividing the annual per capita food supply by 365 days multiplied by 1,000.
4. Nutrient Supply
The nutrient equivalent of the food supply in terms of energy, protein and fats were computed by multiplying the daily per capita food supply in grams by the corresponding nutrient values per 100 grams of the retail weight or "as purchased basis". Further adjustments based on the FNRI Nutrition Survey were made for some commodities from "as purchased basis" into "edible portion" to account for the amount of wastage at the household level. The adjusted values represent the net edible portion of the food supply in terms of energy, protein or fats equivalent.
5. Food Sufficiency
Food sufficiency is a measure of the adequacy of available food supply to meet the food requirements of the population. Expressed in percentage, it is computed by dividing the available supply for daily consumption by the recommended dietary allowance multiplied by 100.
Sufficiency value greater than 100 percent indicates that the available food supply is more than adequate to meet the food requirement of the populace while a value less than 100 percent indicates otherwise.
6. Computing for the Average (Annual) Growth Rates
The annual average growth rate is a measure of the annual rate of growth of a characteristic which is based on the compounded interest rate concept. It is computed using the following formula:
formula.gif (665 bytes)
g = average annual growth rate
xt = value of the characteristic at time t
xo = value of the characteristic at the start of the 
reference period
t = years elapsed since the start up to the end 
of the reference period