Various food measurements on the market
The Ghana Statistical Service (GSS) has revealed significant differences in the weight of commonly used food measurement units across the country, highlighting the need for standardisation to improve the accuracy of agricultural statistics.
The findings are contained in three publications released under the Non-Standard Units Survey (NSUS), conducted in collaboration with the Ministry of Food and Agriculture (MoFA).
According to the reports, the same cups, tins, sacks and size classifications used daily in homes, markets and at farm gates often represent different quantities depending on the region, making it difficult to compile reliable national data on agriculture, food security and the economy.
The survey found, that a small-sized cup of local rice weighs an average of 0.352 kilogrammes nationally but ranges from 0.320 kilogrammes in the Savannah Region to 0.378 kilogrammes in the Greater Accra Region.
Similarly, a medium-sized margarine tin used in markets has a national average weight of 0.276 kilogrammes, but weighs as little as 0.228 kilogrammes in the Ahafo Region and as much as 0.346 kilogrammes in the Ashanti Region.
The Household Report also revealed that a small-sized Puna yam weighs an average of 1.043 kilogrammes nationwide but reaches 1.564 kilogrammes in the Bono Region, while the weight of a medium-sized cup of gari differs from 0.267 kilogrammes in Bono East to 0.292 kilogrammes in the Eastern Region.
At the farmgate level, the survey uncovered even wider disparities.
The commonly used cocoa (jute) sack for dried yellow maize weighs between 131.1 kilogrammes in Greater Accra Region and 198 kilogrammes in Bono East Region, a difference of nearly 67 kilogrammes.
The report further showed that size descriptions such as small, medium and large are often unreliable indicators of actual weight, whereas container-based measures used for oils generally provide more consistent results because of their fixed capacities.
To address these inconsistencies, GSS has developed nationally representative conversion factors that translate commonly used non-standard units, including olonka tins, cups, heaps, bundles, bottles and size-based classifications, into standard metric measurements.
The Statistical Service said the conversion factors would improve the quality and comparability of agricultural data used to estimate production, trade, consumption, food security, Gross Domestic Product (GDP) and the Consumer Price Index (CPI).
According to GSS, the reports represent a major milestone in Ghana’s agricultural statistical system by providing policymakers, researchers, development partners and other data users with reliable evidence for planning and decision-making.
The Service added that the new conversion factors will help ensure greater consistency in agricultural data collection and strengthen evidence-based policy formulation for the country’s development.
By Vera Owusu Sarpong