This post is part of a series on HarvestChoice data methodology. Today’s tool: the Crop Reporter.
Among the tools available on the HarvestChoice website is the Crop Reporter (CR). The CR facilitates the tabulation of harvested area, production and yield, as well as value of production for a number of crops, crop groups, countries and country groups around the world.
The data source for the CR is FAOSTAT. HarvestChoice then transforms the numbers using a series of calculations to fit the tool's purpose. To keep it relevant, we update the underlying tables for the CR in line with FAO’s posting of new data.
This post describes the data and calculations underlying the CR, as well as the rational for choosing between one number versus another.
Step 1: Download FAO Data
For efficiency, we download bulk data (all products, countries and years) from the FAO domain Production of Crops and separately download the complete series of World Gross Production Value (constant 2004-2006 1000 I$) for all crops. As the new FAOSTAT website was still under construction, we used the old FAOSTAT website.
Step 2: Convert FAO Data
We then upload all the downloaded FAO data into an Access Database with a format suitable for our purpose.
Step 3: Calculate Country-Wise Value of Production
From the World Gross Production Value (in constant I$) it is possible to compute the product price for each crop, which is the same for all years of the series, and can be applied to any country thereafter.
IntPrice(crop) = World_ValProd(crop) * 1000 / World_Production(crop)
The crops produced in each country are matched against the resulting prices, and whenever there is no corresponding price, research on the web or calculations based on previously available prices or similar products provide the data for the missing price.
With the complete price table for all crops, we can then calculate a time series of production value for all crops in each country.
Step 4: Aggregate Crops and Countries
We aggregate crops and countries the following ways (and included groups exclusive of certain key countries):
Crops are aggregated into major crop groups (guided by FAO’s classifications): cereals, oil crops, fiber crops, vegetables, pulses, roots and tubers, and tree nuts; and
Countries are aggregated into economic and/or geographic groups.
All the aggregations for area, production and value of production are done by simple summation, the aggregation for yield is a weighted sum:
Step 5: Calculation of Growth Rates
Besides simple figures, the CR also shows growth rates between the years displayed. This is the average growth rate between the shown years in percent:
(logest(val1..valN, year1..yearN) -1 ) * 100
Step 6: Select years to be included in the CR
FAO’s time series on crop production (and livestock) start in 1961 and the latest year reported (in June 2012) is 2010 – the last year typically being FAO (F) estimates, unofficial figures (*) or imputed data (Imp). Data flags – the F, * or Imp above, are not displayed in the CR.
In the current update of the CR we tried to show decadal growth rates, which unfortunately have to start with 1961, but then start with each decade’s first year. They are thus: 1961-1969, 1970-1979, 1980-1989, 1990-1999, 2000-2009, and, for the sake of completeness 2000-2010.