Note: This post (and the underlying report) was updated after additional research and analysis.
Summary:
We find that advocacy for sugar-sweetened beverages taxes to control diabetes mellitus type 2 to be highly-cost effective (~72,131 DALYs per USD 100,000, which is at least 10x as cost-effective as giving to a GiveWell top charity).
Beyond raw cost-effectiveness estimates (which are highly uncertain), the cause looks highly promising, given the high quality of evidence underlying the theory of change.
Reinforcing this, the expert consensus supports the fact that this is an effective solution for a growing problem.
Further support comes from the fact the harder-to-quantify downsides to the intervention (e.g. lower freedom of choice) are marginal.
Our detailed cost-effectiveness can be found here, as can the full report be read here.
Introduction: This report on diabetes mellitus type 2 is the culmination of three iterative rounds of research: (i) an initial shallow research round involving 1 week of desktop research; (ii) a subsequent intermediate research round involving 2 weeks of desktop research and expert interviews; and (iii) a final deep research round involving 3 weeks of desktop research, expert interviews, and the commissioning of surveys and quantitative modelling.
Importance: Diabetes is a chronic disease characterized by elevated levels of blood sugar, which over time leads to serious damage to the body, with type 2 diabetes in particular occurring when the body becomes resistant to insulin or becomes unable to produce enough insulin. Globally, diabetes mellitus type 2 is certainly a problem, and causes a direct health burden of 90 million disability-adjusted life years (DALYs) in 2024, as well as an indirect health burden of 2 million DALYs from an increased risk of depression amongst diabetes sufferers. There is also an accompanying net economic burden equivalent to foregoing the doubling of income for 191 million people; note that people typically value such income doublings at around 1/ā5th of a year of healthy life. And this problem of diabetes is only expected to grow between 2024 and 2100, as a result of factors like economic development, ageing, and population growth.
Neglectedness: Government policy is far from adequate, with only 20% of the potential reduction in diabetes burden from implementing sugar-sweetened beverages taxes already being captured by existing government policy; this is not expected to change much going forward ā based on the historical track record, any individual country has only a 1% chance per annum of introducing such policies. At the same time, while there are NGOs working on diabetes and sugar-sweetened beverages taxes (e.g. a big Bloomberg-funded organization does work in Brazil, Colombia, Jamaica, Barbados and South Africa), expansion of such work is conditional on funding, and fundamentally, efforts in the area are not equal to the massive and growing disease burden.
Tractability: There are many potential solutions to the problem of diabetes mellitus type 2 (e.g. sugar-sweetened beverages taxes, or mandatory reformulation, or pharmaceutical interventions); however, we find that the most cost-effective solution is likely to be advocacy for sugar-sweetened beverages (SSB) taxes. The theory of change behind this intervention is as such:
Step 1: Lobby a government to implement a sugar-sweetened beverages tax.
Step 2: A sugar-sweetened beverages tax reduces consumption of sugar-sweetened beverages in a single country.
Step 3: Reduced consumption of sugar-sweetened beverages in a single country reduces the global disease burden of diabetes mellitus type 2.
Using the track record of past SSB tax and sodium control advocacy efforts and of general lobbying attempts (i.e. an āoutside viewā), and combining this with reasoning through the particulars of the case (i.e. an āinside viewā), our best guess is that policy advocacy for top sodium reduction policies has a 8% chance of success per campaign. Meanwhile, based on various meta-analyses, and after robust discounts and checks (e.g. for a conservative theoretical prior of a null hypothesis; for endogeneity; for study populations being unrepresentative; or for publication bias), we expect that a WHO-recommended 20% tax on sugar-sweetened beverages will reduce consumption of sugar-sweetened beverages by 12%; and in turn, a 100% reduction in sugar-sweetened beverages consumption in a single country will reduce the global disease burden of diabetes mellitus type 2 by 0.02%.
There are additional externalities and complications to an SSB tax. On the positive side, (a) an SSB tax also reduces ischaemic heart disease (n.b. an increase in impact relative to the diabetes-only baseline by 200%). On the negative side, (b) we expect on average a 7 year gap between when an advocacy intervention begins and when the health impact actually kicks (-5% impact); (c) taxing SSBs risks causing consumers to switch to alcohol (-30% impact); and (d) taxing SSBs leads to reduced freedom of choice (-0.5% impact). Most significantly, however, is the potential gain in cost-effectiveness (+600%) from implementing the intervention in the most promising countries rather than the average one ā that is, those countries suffering from some combination of a higher national disease burden, greater neglect by their governments and NGOs, and state fragility.
Implementation Issues: From our interviews with NGOs working in the space, we find that funding is scarce. On the issue of whether a talent gap exists, however, opinion was more mixed.
Outstanding Uncertainties: There are a number of outstanding uncertainties, of which the three most important involve: (a) our use of point estimations (n.b. relying on them is reasonable given that we are ultimately interested in mean estimates, but caution is also warranted, as significant variance is possible); (b) the very simplified methodology we use to project the future disease burden of diabetes mellitus type 2; and (c) the highly uncertain estimates of the probability of advocacy success.
Conclusion: Overall, our view is that advocacy for sugar-sweetened beverages tax to control diabetes mellitus type 2 is an extremely cost-effective cause , and we recommend that charity incubators, grantmakers, policy advocacy organizations, and governments themselves, consider directing more resources towards this area.
Postscript: Weāve updated our analysis of the issue of whether and how much freedom of choice is diminished by a soda tax. We would like to thank the various commentators who gave feedback, though we also understand that they may still have reasonable disagreements over our methodology and results, especially given different philosophical and epistemic priors on the matter.
Deep Report on Diabetes
Note: This post (and the underlying report) was updated after additional research and analysis.
Summary:
We find that advocacy for sugar-sweetened beverages taxes to control diabetes mellitus type 2 to be highly-cost effective (~72,131 DALYs per USD 100,000, which is at least 10x as cost-effective as giving to a GiveWell top charity).
Beyond raw cost-effectiveness estimates (which are highly uncertain), the cause looks highly promising, given the high quality of evidence underlying the theory of change.
Reinforcing this, the expert consensus supports the fact that this is an effective solution for a growing problem.
Further support comes from the fact the harder-to-quantify downsides to the intervention (e.g. lower freedom of choice) are marginal.
Our detailed cost-effectiveness can be found here, as can the full report be read here.
Introduction: This report on diabetes mellitus type 2 is the culmination of three iterative rounds of research: (i) an initial shallow research round involving 1 week of desktop research; (ii) a subsequent intermediate research round involving 2 weeks of desktop research and expert interviews; and (iii) a final deep research round involving 3 weeks of desktop research, expert interviews, and the commissioning of surveys and quantitative modelling.
Importance: Diabetes is a chronic disease characterized by elevated levels of blood sugar, which over time leads to serious damage to the body, with type 2 diabetes in particular occurring when the body becomes resistant to insulin or becomes unable to produce enough insulin. Globally, diabetes mellitus type 2 is certainly a problem, and causes a direct health burden of 90 million disability-adjusted life years (DALYs) in 2024, as well as an indirect health burden of 2 million DALYs from an increased risk of depression amongst diabetes sufferers. There is also an accompanying net economic burden equivalent to foregoing the doubling of income for 191 million people; note that people typically value such income doublings at around 1/ā5th of a year of healthy life. And this problem of diabetes is only expected to grow between 2024 and 2100, as a result of factors like economic development, ageing, and population growth.
Neglectedness: Government policy is far from adequate, with only 20% of the potential reduction in diabetes burden from implementing sugar-sweetened beverages taxes already being captured by existing government policy; this is not expected to change much going forward ā based on the historical track record, any individual country has only a 1% chance per annum of introducing such policies. At the same time, while there are NGOs working on diabetes and sugar-sweetened beverages taxes (e.g. a big Bloomberg-funded organization does work in Brazil, Colombia, Jamaica, Barbados and South Africa), expansion of such work is conditional on funding, and fundamentally, efforts in the area are not equal to the massive and growing disease burden.
Tractability: There are many potential solutions to the problem of diabetes mellitus type 2 (e.g. sugar-sweetened beverages taxes, or mandatory reformulation, or pharmaceutical interventions); however, we find that the most cost-effective solution is likely to be advocacy for sugar-sweetened beverages (SSB) taxes. The theory of change behind this intervention is as such:
Step 1: Lobby a government to implement a sugar-sweetened beverages tax.
Step 2: A sugar-sweetened beverages tax reduces consumption of sugar-sweetened beverages in a single country.
Step 3: Reduced consumption of sugar-sweetened beverages in a single country reduces the global disease burden of diabetes mellitus type 2.
Using the track record of past SSB tax and sodium control advocacy efforts and of general lobbying attempts (i.e. an āoutside viewā), and combining this with reasoning through the particulars of the case (i.e. an āinside viewā), our best guess is that policy advocacy for top sodium reduction policies has a 8% chance of success per campaign. Meanwhile, based on various meta-analyses, and after robust discounts and checks (e.g. for a conservative theoretical prior of a null hypothesis; for endogeneity; for study populations being unrepresentative; or for publication bias), we expect that a WHO-recommended 20% tax on sugar-sweetened beverages will reduce consumption of sugar-sweetened beverages by 12%; and in turn, a 100% reduction in sugar-sweetened beverages consumption in a single country will reduce the global disease burden of diabetes mellitus type 2 by 0.02%.
There are additional externalities and complications to an SSB tax. On the positive side, (a) an SSB tax also reduces ischaemic heart disease (n.b. an increase in impact relative to the diabetes-only baseline by 200%). On the negative side, (b) we expect on average a 7 year gap between when an advocacy intervention begins and when the health impact actually kicks (-5% impact); (c) taxing SSBs risks causing consumers to switch to alcohol (-30% impact); and (d) taxing SSBs leads to reduced freedom of choice (-0.5% impact). Most significantly, however, is the potential gain in cost-effectiveness (+600%) from implementing the intervention in the most promising countries rather than the average one ā that is, those countries suffering from some combination of a higher national disease burden, greater neglect by their governments and NGOs, and state fragility.
Implementation Issues: From our interviews with NGOs working in the space, we find that funding is scarce. On the issue of whether a talent gap exists, however, opinion was more mixed.
Outstanding Uncertainties: There are a number of outstanding uncertainties, of which the three most important involve: (a) our use of point estimations (n.b. relying on them is reasonable given that we are ultimately interested in mean estimates, but caution is also warranted, as significant variance is possible); (b) the very simplified methodology we use to project the future disease burden of diabetes mellitus type 2; and (c) the highly uncertain estimates of the probability of advocacy success.
Conclusion: Overall, our view is that advocacy for sugar-sweetened beverages tax to control diabetes mellitus type 2 is an extremely cost-effective cause , and we recommend that charity incubators, grantmakers, policy advocacy organizations, and governments themselves, consider directing more resources towards this area.
Postscript: Weāve updated our analysis of the issue of whether and how much freedom of choice is diminished by a soda tax. We would like to thank the various commentators who gave feedback, though we also understand that they may still have reasonable disagreements over our methodology and results, especially given different philosophical and epistemic priors on the matter.