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Food availability is defined as the availability of sufficient quantities of food of appropriate quality supplied through domestic production or importation (bought outside the household or scale or reference). Food availability indicator measures the amount of food produced by the household, and the amount that is sold and purchased per capita in order to estimate the calories and nutrients available per capita (Remans et al. 2013). In addition, this measure may also include a subjective food availability index that may be based on household report on the number of months or days of food insecurity. At the field level, scientists may use an alternative approach to estimate the potential calories available to the household at a given production level. This may be done by estimation of the total calories and nutrients produced and using participatory approaches to infer how the farmer might use this crop or livestock output.
How to operationalize the metric
Method of data collection and data needed to compute the method:
Data to estimate this metrics are usually collected using a survey at the household level. The main data needed from the surveys for calculation include the following:
- Amount of crops produced by the household in standard metric units (e.g., kilograms, liters)
- Amount of crop produce that is sold
- Amount of food that is purchased from the market for consumption
- Amount of livestock and animal based products that is produced
- Amount of livestock and animal based products that is sold
- Household composition (e.g., members by age and gender)
The data on the household composition (age and gender of household members) are useful in determining the dietary intake of each individual with a focus on calories and nutrients. Food composition tables are used to provide an estimate of the amount of calories in a 100 g of a given crop (e.g., maize) and the nutrients contained in that crop. The food composition tables have been developed by the Food and Agricultural Organization (FAO) (FAO, 2016). Additionally, universities such as the Harvard University School of Public Health have developed food composition tables that are country specific, for example one developed for Tanzania (HSPH, 2016). The food composition tables provide data on the calories and nutrient per food item. For the analysis, the focus is on seven essential nutrients: carbohydrates, protein, vitamin A, vitamin C, iron, zinc, and folate. An adult equivalent scale is used to estimate total food requirements of an individual. Adult equivalent values provide an estimate by age and gender of caloric requirement of an individual based on the mean requirements by age and gender (Claro et al., 2010). In addition, dietary reference intake (DRI) values may be used in this estimation. The DRIs provide quantitative reference values of the nutrient intakes needed for a healthy living (USDA, 2017). For the estimation, we need to account for amount of food waster or lost postharvest. Data on food waste from production may be obtained either from the survey tool or from secondary sources such as FAO estimate of lost production from postharvest loss, consumption, and processing (FAO, 2011)
Unit of analysis:
The food availability indicator is scored from 0 to 1. The calories or nutrients available per capita are estimated as follows:
- To calculate the amount of food available per crop, subtract the amount sold and amount lost to waste from the total amount produced by the household.
- To find the total amount available, add to this estimate the total amount of this crop that the household bought for consumption. The total food items available are then multiplied with the data from the food composition table to obtain the nutrients (seven nutrients) and calories (in kilo calories per 100 g). For example, if maize grain is one of the food items, obtain the number of calories per 100 g of maize grain from the food composition table. In addition, the table contains the nutrients content per item. The data from the seven nutrients should be listed. If the nutrient is not part of maize grain, indicate a “0”
- To obtain the amount of calories and nutrient available per capita per day for the households, sum up the calories and nutrients across all the food items and divide by the adult equivalent of the household.
Limitations regarding estimating and interpreting: