p u b l i c h e a l t h 1 2 9 ( 2 0 1 5 ) 1 2 8 8 e1 2 9 0
Available online at www.sciencedirect.com
Public Health journal homepage: www.elsevier.com/puhe
Short Communication
Hunger measurement complexity: is the Global Hunger Index reliable? Hirotsugu Aiga a,b,* a Human Development Department, Japan International Cooperation Agency (JICA), Nibancho Center Bldg, 5-25 Niban-cho, Chiyoda-ku, Tokyo 102-8012, Japan b Department of Global Health, Milken Institute School of Public Health, The George Washington University, 4th Floor, 950 New Hampshire Ave. NW, Washington, DC 20052, USAc
article info Article history:
complex methodological challenge which should not be crudely addressed by such an oversimplified concept and definition as the GHI employs.
Received 11 November 2014 Received in revised form 16 April 2015 Accepted 22 April 2015
Two technical flaws in concept and definition of the GHI
Available online 29 May 2015
Technical flaw due to indicator-aggregation without weighting
Introduction In October 2013, the International Food Policy Research Institute (IFPRI) published the eighth Global Hunger Index (GHI) report.1 Since 2006, a series of annual GHI report launches have been welcomed, by providing both the global health community and the international development community with an opportunity to be regularly updated on the hunger and food insecurity situation of respective countries.2,3 The GHI is a composite index constructed by aggregating three equally weighted indicators (proportion of population undernourished by FAO, prevalence of underweight children under five years of age by WHO; and under-five mortality rate by UNICEF) into an average.1 Yet, there are two major technical flaws on accuracy of the GHI in estimating magnitude and severity of hunger. Note that hunger measurement is a
First, averaging the three component indicators without weighting is questionable. The proportion of the population undernourished reasonably represents the magnitude of food insecurity or hunger. Undernourishment leads to becoming underweight and chronic underweight thereby leads to the risks of disease and ultimately to death. Thus, combining two hunger-consequence indicators (i.e. prevalence of underweight children under five years of age and under-five mortality rate) with the proportion of population undernourished reasonably adds the elements of the severity or depth of hunger to the GHI. However, the current GHI methodologies overlook or overestimate the both probability of becoming underweight through being undernourished and probability of mortality through being underweight. Becoming underweight is attributable not exclusively to food insecurity or hunger, but also to two other types of underlying causes: inadequate care and feeding practices; and unhealthy household environment and inadequate health services.4 Therefore, the prevalence of underweight children
* Corresponding author. Human Development Department, Japan International Cooperation Agency (JICA), Nibancho Center Bldg, 5-25 Niban-cho, Chiyoda-ku, Tokyo 102-8012, Japan. Tel.: þ81 3 5226 9329; fax: þ81 3 5226 6389. E-mail address: [email protected]. c Tel.: þ1 202 994 5179; fax: þ1 202 994 3773. http://dx.doi.org/10.1016/j.puhe.2015.04.019 0033-3506/© 2015 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.
p u b l i c h e a l t h 1 2 9 ( 2 0 1 5 ) 1 2 8 8 e1 2 9 0
under five years of age should be not unweighted, but rather appropriately weighted. There has been neither global systematic review nor meta-analysis that estimated the level of contribution of food insecurity or hunger to becoming underweight. There have been even fewer studies which concluded household food insecurity results in childhood underweight.5 Therefore, considering that food insecurity is one of the three types of causes of underweight, it could tentatively assumed that one third (33%) the weight should be given to the prevalence of underweight children under five years of age in the GHI. In other words, two thirds of underweight component of the GHI, which accounts for one third of total GHI value due to equally unweighted aggregation of the three component indicators, are attributable to non-foodinsecurity or non-hunger elements. Thus, 22% of the GHI (¼1/3 2/3) represent underweight derived from non-foodinsecurity or non-hunger conditions (Fig. 1). Moreover, half of all deaths among children under five years of age are attributed to being underweight.6,7 As aforementioned, it could be assumed that one third (33%) the weight should be given to the prevalence of underweight children under five years of age in the GHI. Therefore, only one-sixth (¼1/3 1/2 ¼ 1/6) of all child deaths are attributable to food insecurity or hunger. In other words, five sixths of under-five mortality rate are attributable to non-foodinsecurity or non-hunger elements. Thus, 28% of the GHI (¼1/3 5/6) represent mortalities derived from non-foodinsecurity or non-hunger conditions (Fig. 1). To exclude the proportion of child deaths attributable to the causes unrelated to food insecurity or hunger, one-sixth (17%) the weight should be given to under-five mortality rate in the GHI.
How do the GHI figures change after weighting adjustment? By applying the proposed weights to prevalence of underweight children under five years of age and under-fivemortality-rate in the original GHI dataset,1 adjusted GHI was defined as Eq. [2] and calculated for each country. Relative error was further calculated for each country, by applying Eq [3].
1289
GHIo ¼ (PUN þ CUW þ CM)/3
[1]
where, GHI0: original GHI without weighting, PUN: proportion of population undernourished (%), CUW: prevalence of underweight children under five years of age (%), CM: underfive-mortality-rate (%)
GHIa ¼ (PUN 1 þ CUW 1/3 þ CM 1/3 1/2)/(1 þ 1/3 þ 1/3 1/2) ¼ 2/3PUN þ2/9CUW þ1/9CM
[2]
where, GHIa: adjusted GHI with weighting PUN: proportion of population undernourished (%) CUW: prevalence of underweight children under five years of age (%) CM: under-fivemortality-rate (%) Relative errorð%Þ ¼ jGHIa GHI0 j=GHIa 100
[3]
Comparison between original GHI (GHIo) and adjusted GHI (GHIa) figures provides several interesting findings. China, one of the countries reported as top 10 ‘Winners’ by IFPRI,1 became ranked 21st. Instead, Guyana became ranked eighth as top 10 ‘Winners’ after GHI adjustment. While only five countries (Guatemala, Paraguay, Burundi, Swaziland and Comoros) were reported to have increased GHIo between 1990 and 2013 as ‘Loser’ countries,1 there are a total of 13 countries where GHIa increased after the adjustment. Insensitive use of terms ‘Winners’ and ‘Losers’ as categorization of countries could create unnecessary political debates. Note that, when the World Health Report 2000 was launched, we learnt numerous lessons on a need for careful analyses for publishing international rankings by country.8 Mean of relative errors of 120 countries was 22%. This implies that the inclusion of nonfood-insecurity or non-hunger elements in GHI causes 22% systematic relative errors on average across the countries, in estimating magnitude and severity of hunger.
Technical flaw due to inadequate representativity to entire population Second, the definition of the GHI does not adequately address the limitations of the proportion of population
Fig. 1 e Global Hunger Index components attributable to food insecurity or hunger.
1290
p u b l i c h e a l t h 1 2 9 ( 2 0 1 5 ) 1 2 8 8 e1 2 9 0
undernourished and prevalence of underweight children under five years of age, in representing hunger. The proportion of population undernourished is not a prevalence indicator derived from individuals’ food consumption data, but a macro-economic indicator derived from per-capita food availability.9 Thus, it does not help in characterizing the hungry, i.e. who they are, where they are, and how they look. Thus, the use of the indicator does not help correctly determine the populations in need of interventions. The prevalence of underweight children under five years of age cannot be simply extrapolated to that of older age groups.10 Thus, measurement of hunger among population five years of age and older, which account for 91% of global populations were not adequately considered and adjusted in the GHI.
Conclusion The GHI composed of three equally distributed indicators in an unweighted average looks convincing at first glance, but it is not in reality. Thus, only 50% of the GHI (¼1/3 þ [1/3 1/ 3] þ [1/3 1/6]) account for food-insecurity-related or hungerrelated elements (Fig. 1). The other 50% account for non-foodinsecurity or non-hunger elements. This inclusion error of non-food-insecurity or non-hunger elements must not continue to be ignored. Each figure of any index or indicator will have wings, once it is published. To avoid misguiding national and global food security policies by referring to the current GHI, we should warn ourselves about more accurate definition of the GHI. In addition, to prevent unnecessary political debates that stem from the GHI, a more sensitive approach should be taken for country rankings based on GHI figures. Considering a series of increasingly critical debates on national food security policies worldwide, the importance of the GHI and other food security indicators is increasing.10 The technical reliability of the GHI needs to improve by re-visiting and re-examining its concept and definition, in view of its significant influence on global policy.
Author statements Acknowledgements None.
Ethical approval I don't have ethical approval from the institutional review board. As this paper does not involve analysis and collection of individuals' data (i.e. tissue/blood/urine/stool tests, observation and interview), it was not required to get ethical approval.
Funding I have not received any fund for this research work.
Competing interests I declare that I have no competing interest. The views and opinions expressed by the independent author in this publication are provided in his personal capacity and are his sole responsibility.
references
1. International Food Policy Research Institute (IFPRI). Global hunger index: the challenge of hunger: building resilience to achieve food and nutrition security. Washington DC: IFPRI; 2013. 2. Arie S. Millennium goal on hunger is within reach, but food instability threatens progress. BMJ 2012;345:e6961. 3. Lancet The. The complex challenge of hunger. Lancet. 2013;382(9902):1382. 4. UNICEF. Improving child nutrition: the achievable imperative for global progress. New York: UNICEF; 2013. 5. Aiga H, Matsuoka S, Kuroiwa C, Yamamoto S. Malnutrition among the children in the rural Malawian fish-farming households. Trans R Soc Trop Med Hyg 2009;103(8):827e33. 6. Rice AL, Sacco L, Hyder A, Black R. Malnutrition as an underlying cause of childhood deaths associated with infectious diseases in developing countries. Bull World Health Organ 2000;78(10):1207e21. 7. Black RE, Morris SS, Bryce J. Where and why are 10 million children dying every year? Lancet. 2003;361(9376):2226e34. 8. Ollila E, Koivusalo M. The World Health report 2000: World Health Organization health policy steering off coursechanged values, poor evidence, and lack of accountability. Int J Health Serv 2002;32(3):503e14. 9. Food and Agriculture Organization of United Nations. The state of food insecurity in the world 2013. Rome: FAO; 2013. 10. Aiga H. How many people are really hungry? Lancet. 2008;372(9647):1367e9.
Available online at www.sciencedirect.com
Public Health journal homepage: www.elsevier.com/puhe
Short Communication
Hunger measurement complexity: is the Global Hunger Index reliable? Hirotsugu Aiga a,b,* a Human Development Department, Japan International Cooperation Agency (JICA), Nibancho Center Bldg, 5-25 Niban-cho, Chiyoda-ku, Tokyo 102-8012, Japan b Department of Global Health, Milken Institute School of Public Health, The George Washington University, 4th Floor, 950 New Hampshire Ave. NW, Washington, DC 20052, USAc
article info Article history:
complex methodological challenge which should not be crudely addressed by such an oversimplified concept and definition as the GHI employs.
Received 11 November 2014 Received in revised form 16 April 2015 Accepted 22 April 2015
Two technical flaws in concept and definition of the GHI
Available online 29 May 2015
Technical flaw due to indicator-aggregation without weighting
Introduction In October 2013, the International Food Policy Research Institute (IFPRI) published the eighth Global Hunger Index (GHI) report.1 Since 2006, a series of annual GHI report launches have been welcomed, by providing both the global health community and the international development community with an opportunity to be regularly updated on the hunger and food insecurity situation of respective countries.2,3 The GHI is a composite index constructed by aggregating three equally weighted indicators (proportion of population undernourished by FAO, prevalence of underweight children under five years of age by WHO; and under-five mortality rate by UNICEF) into an average.1 Yet, there are two major technical flaws on accuracy of the GHI in estimating magnitude and severity of hunger. Note that hunger measurement is a
First, averaging the three component indicators without weighting is questionable. The proportion of the population undernourished reasonably represents the magnitude of food insecurity or hunger. Undernourishment leads to becoming underweight and chronic underweight thereby leads to the risks of disease and ultimately to death. Thus, combining two hunger-consequence indicators (i.e. prevalence of underweight children under five years of age and under-five mortality rate) with the proportion of population undernourished reasonably adds the elements of the severity or depth of hunger to the GHI. However, the current GHI methodologies overlook or overestimate the both probability of becoming underweight through being undernourished and probability of mortality through being underweight. Becoming underweight is attributable not exclusively to food insecurity or hunger, but also to two other types of underlying causes: inadequate care and feeding practices; and unhealthy household environment and inadequate health services.4 Therefore, the prevalence of underweight children
* Corresponding author. Human Development Department, Japan International Cooperation Agency (JICA), Nibancho Center Bldg, 5-25 Niban-cho, Chiyoda-ku, Tokyo 102-8012, Japan. Tel.: þ81 3 5226 9329; fax: þ81 3 5226 6389. E-mail address: [email protected]. c Tel.: þ1 202 994 5179; fax: þ1 202 994 3773. http://dx.doi.org/10.1016/j.puhe.2015.04.019 0033-3506/© 2015 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.
p u b l i c h e a l t h 1 2 9 ( 2 0 1 5 ) 1 2 8 8 e1 2 9 0
under five years of age should be not unweighted, but rather appropriately weighted. There has been neither global systematic review nor meta-analysis that estimated the level of contribution of food insecurity or hunger to becoming underweight. There have been even fewer studies which concluded household food insecurity results in childhood underweight.5 Therefore, considering that food insecurity is one of the three types of causes of underweight, it could tentatively assumed that one third (33%) the weight should be given to the prevalence of underweight children under five years of age in the GHI. In other words, two thirds of underweight component of the GHI, which accounts for one third of total GHI value due to equally unweighted aggregation of the three component indicators, are attributable to non-foodinsecurity or non-hunger elements. Thus, 22% of the GHI (¼1/3 2/3) represent underweight derived from non-foodinsecurity or non-hunger conditions (Fig. 1). Moreover, half of all deaths among children under five years of age are attributed to being underweight.6,7 As aforementioned, it could be assumed that one third (33%) the weight should be given to the prevalence of underweight children under five years of age in the GHI. Therefore, only one-sixth (¼1/3 1/2 ¼ 1/6) of all child deaths are attributable to food insecurity or hunger. In other words, five sixths of under-five mortality rate are attributable to non-foodinsecurity or non-hunger elements. Thus, 28% of the GHI (¼1/3 5/6) represent mortalities derived from non-foodinsecurity or non-hunger conditions (Fig. 1). To exclude the proportion of child deaths attributable to the causes unrelated to food insecurity or hunger, one-sixth (17%) the weight should be given to under-five mortality rate in the GHI.
How do the GHI figures change after weighting adjustment? By applying the proposed weights to prevalence of underweight children under five years of age and under-fivemortality-rate in the original GHI dataset,1 adjusted GHI was defined as Eq. [2] and calculated for each country. Relative error was further calculated for each country, by applying Eq [3].
1289
GHIo ¼ (PUN þ CUW þ CM)/3
[1]
where, GHI0: original GHI without weighting, PUN: proportion of population undernourished (%), CUW: prevalence of underweight children under five years of age (%), CM: underfive-mortality-rate (%)
GHIa ¼ (PUN 1 þ CUW 1/3 þ CM 1/3 1/2)/(1 þ 1/3 þ 1/3 1/2) ¼ 2/3PUN þ2/9CUW þ1/9CM
[2]
where, GHIa: adjusted GHI with weighting PUN: proportion of population undernourished (%) CUW: prevalence of underweight children under five years of age (%) CM: under-fivemortality-rate (%) Relative errorð%Þ ¼ jGHIa GHI0 j=GHIa 100
[3]
Comparison between original GHI (GHIo) and adjusted GHI (GHIa) figures provides several interesting findings. China, one of the countries reported as top 10 ‘Winners’ by IFPRI,1 became ranked 21st. Instead, Guyana became ranked eighth as top 10 ‘Winners’ after GHI adjustment. While only five countries (Guatemala, Paraguay, Burundi, Swaziland and Comoros) were reported to have increased GHIo between 1990 and 2013 as ‘Loser’ countries,1 there are a total of 13 countries where GHIa increased after the adjustment. Insensitive use of terms ‘Winners’ and ‘Losers’ as categorization of countries could create unnecessary political debates. Note that, when the World Health Report 2000 was launched, we learnt numerous lessons on a need for careful analyses for publishing international rankings by country.8 Mean of relative errors of 120 countries was 22%. This implies that the inclusion of nonfood-insecurity or non-hunger elements in GHI causes 22% systematic relative errors on average across the countries, in estimating magnitude and severity of hunger.
Technical flaw due to inadequate representativity to entire population Second, the definition of the GHI does not adequately address the limitations of the proportion of population
Fig. 1 e Global Hunger Index components attributable to food insecurity or hunger.
1290
p u b l i c h e a l t h 1 2 9 ( 2 0 1 5 ) 1 2 8 8 e1 2 9 0
undernourished and prevalence of underweight children under five years of age, in representing hunger. The proportion of population undernourished is not a prevalence indicator derived from individuals’ food consumption data, but a macro-economic indicator derived from per-capita food availability.9 Thus, it does not help in characterizing the hungry, i.e. who they are, where they are, and how they look. Thus, the use of the indicator does not help correctly determine the populations in need of interventions. The prevalence of underweight children under five years of age cannot be simply extrapolated to that of older age groups.10 Thus, measurement of hunger among population five years of age and older, which account for 91% of global populations were not adequately considered and adjusted in the GHI.
Conclusion The GHI composed of three equally distributed indicators in an unweighted average looks convincing at first glance, but it is not in reality. Thus, only 50% of the GHI (¼1/3 þ [1/3 1/ 3] þ [1/3 1/6]) account for food-insecurity-related or hungerrelated elements (Fig. 1). The other 50% account for non-foodinsecurity or non-hunger elements. This inclusion error of non-food-insecurity or non-hunger elements must not continue to be ignored. Each figure of any index or indicator will have wings, once it is published. To avoid misguiding national and global food security policies by referring to the current GHI, we should warn ourselves about more accurate definition of the GHI. In addition, to prevent unnecessary political debates that stem from the GHI, a more sensitive approach should be taken for country rankings based on GHI figures. Considering a series of increasingly critical debates on national food security policies worldwide, the importance of the GHI and other food security indicators is increasing.10 The technical reliability of the GHI needs to improve by re-visiting and re-examining its concept and definition, in view of its significant influence on global policy.
Author statements Acknowledgements None.
Ethical approval I don't have ethical approval from the institutional review board. As this paper does not involve analysis and collection of individuals' data (i.e. tissue/blood/urine/stool tests, observation and interview), it was not required to get ethical approval.
Funding I have not received any fund for this research work.
Competing interests I declare that I have no competing interest. The views and opinions expressed by the independent author in this publication are provided in his personal capacity and are his sole responsibility.
references
1. International Food Policy Research Institute (IFPRI). Global hunger index: the challenge of hunger: building resilience to achieve food and nutrition security. Washington DC: IFPRI; 2013. 2. Arie S. Millennium goal on hunger is within reach, but food instability threatens progress. BMJ 2012;345:e6961. 3. Lancet The. The complex challenge of hunger. Lancet. 2013;382(9902):1382. 4. UNICEF. Improving child nutrition: the achievable imperative for global progress. New York: UNICEF; 2013. 5. Aiga H, Matsuoka S, Kuroiwa C, Yamamoto S. Malnutrition among the children in the rural Malawian fish-farming households. Trans R Soc Trop Med Hyg 2009;103(8):827e33. 6. Rice AL, Sacco L, Hyder A, Black R. Malnutrition as an underlying cause of childhood deaths associated with infectious diseases in developing countries. Bull World Health Organ 2000;78(10):1207e21. 7. Black RE, Morris SS, Bryce J. Where and why are 10 million children dying every year? Lancet. 2003;361(9376):2226e34. 8. Ollila E, Koivusalo M. The World Health report 2000: World Health Organization health policy steering off coursechanged values, poor evidence, and lack of accountability. Int J Health Serv 2002;32(3):503e14. 9. Food and Agriculture Organization of United Nations. The state of food insecurity in the world 2013. Rome: FAO; 2013. 10. Aiga H. How many people are really hungry? Lancet. 2008;372(9647):1367e9.
