Harold Alderman MARTIN J. FORMAN MEMORIAL LECTURE Two Dimensions of Growth: Biology and Economics JUN 27, 2019 - 12:15 PM TO 01:45 PM EDT

1. Two Dimensions of Growth:
Biology and Economics
29th Martin J. Forman Memorial Lecture
Harold Alderman
International Food Policy Research Institute (IFPRI)
June 27, 2019

2. Prelude I: Scurvy
Though not currently a major public health concern, scurvy
once was a major cause of mortality.
It claimed up to 2 million deaths in the Age of Sail.
In 1747, James Lind used a randomized clinical trial to
show that lemons cure the malady.
Yet it took a half century before the British navy adopted
its famous prevention policy.

3. Prelude II: Semmelweis
A century after Lind’s experiment, Ignaz Semmelweis
reduced maternal deaths from puerperal fever by 90%
in the clinic he supervised by the simple practice of
washing hands with chlorine solution before attending
deliveries.
He transferred to a second hospital and achieved the
same rate of reduction.
After his term at the hospital expired (and was not
renewed), the practice of handwashing was
abandoned.

4. Two ties to today’s topic
In both cases, what appear in retrospect as obvious
guides to policy failed to gain traction due, in part, to an
inadequate theory to explain the results.
Lind’s contemporaries had no inkling of vitamins, and few
of Semmelweis’s generation knew of even a precursor
to germ theory.
Moreover, in both cases the costs of failing to act with
imperfect information were not weighed against the
costs and benefits of proceeding when there was still
doubt as to the outcome.

5. Numerous plausible links from improved nutrition to
economic growth have been documented
▪ A 1972 MIT workshop [sponsored in part by USAID’s office of
nutrition under Martin Forman] traced this link.
▪ Robert Fogel received a Nobel prize in 1993 recognizing his
work on the contribution of improved nutrition to economic
growth.
▪ Fogel, along with 4 other Nobel laureates, was a juror in 3
Copenhagen Consensus rankings of investments in nutrition
as among the most productive out of scores of programs
considered.

6. Plausible, but not proven
Myriad RCTs show causal chains from nutrition trials to
short-term physical and cognitive outcomes.
There is little doubt that cognitive (and non-cognitive) ability
contributes to schooling and that wages respond to years
in school and learning.
BUT we seldom follow a child who participated in a RCT to
adulthood.
Even those trials, as well as alternative approaches to
establishing counterfactuals, raise questions of external
validity and scalability.

7. How the plausible argument is often made:
an example
Hoddinott et al. estimated global returns to nutrition, linking a
20% reduction in stunting if 10 key interventions were scaled
up as modeled in the 2013 Lancet.
Reduced stunting led to higher GNP; benefit-cost ratios could
be as high as 34:1 for India.
Estimates were based on productivity gains observed in
longitudinal RCT from Guatemala but were also linked to
specific country GNP growth rates.
The results are robust; the story would be the same if based on
productivity gains observed in Zimbabwe or global
associations of height and GNP were substituted.

8. Such estimates are driven by the association of
stunting and wages
Evidence that taller individuals earn more comes from diverse
settings: India, Pakistan, and the Philippines but also Brazil
and the US.
But, this may reflect the indirect effect of height on status.
Another driver is through schooling, the main pathway from
height to higher wages in the Guatemala RCT.
It is almost a cottage industry to use quasi-experimental
approaches to show that stunting affects either age at entry or
total years in school or both.
This may be a form of height as a proxy; both families and
teachers use height as an indicator of school readiness.

9. One path from stature to development is
mediated by how we respond

10. Still the association of stunting and earnings
goes beyond years of school
With increasing global school participation rates, the contribution
of stunting to wages is likely to come through learning,
conditional on years of schooling.
Consistent with this, various studies find strong associations of
stunting and delayed or impaired cognitive development.
While stunting is an indicator of overall health and home
environment, it is difficult to determine whether stunting is
directly causal for cognitive ability.
This is a point my colleague, Jef Leroy, has recently stressed.
In any case, stunting ≠ stature and, further, stature ≠ nutrition.

11. A case in point
Exclusive breastfeeding – probably the most universal
nutrition recommendation – has little impact on stature.
It does significantly reduce morbidity, particularly where
water sources are questionable. An additional global
impact is through increases in IQ.
While small in effect size (2.6 IQ points in LMICS), the
scale of the practice implies a significant aggregate
economic loss from shortened breastfeeding; the loss was
estimated at $302 billion for 2012.

12. And another
Iodine fortification for pregnant women has been an idée
fixe for UNICEF.
The physiology for maternal hormone production is well
known and the epidemiology of IQ and severe iodine
deficiency is persuasive.
As is the reduction of risk of neonatal mortality
And the benefit-cost ratios for fortification are in the double
digits
Yet, again, there is no clear role in stature for children

13. Yet one more example
There are many good reasons to provide pregnant women
with iron [and folate] supplements and to provide
fortification to young children.
But preventing stunting isn’t the main one.
Even the evidence on the impact of prenatal iron and
subsequent cognition is currently mixed.
Nevertheless, economic returns to iron fortification may still
be substantial; work capacity is often enhanced as is
cognitive functioning in youths and adults.

14. Parsing the plausible pathway
Reducing malnutrition can:
i. Reduce infant and child mortality (but it is a challenge to
assign a value to these benefits) [✓]
ii. Reduce costs of healthcare for neonates, infants, and
children [✓]
iii. Reduce costs of obesity and chronic diseases [1/2 ✓]
iv. Increase productivity by increasing strength [1/2 ✓]
v. Increase productivity by increasing ability [✓]

15. For the remainder of the talk I am going to focus on v. –
pathways to ability. In particular, I’ll focus on the role of
stunting per se.
I’ll assume that the savings in child health costs are real,
but small compared to potential productivity gains.
The returns to investing in nutrition to reduce chronic
disease are less clear, so I will mention those briefly.
But first, I want to briefly discuss why mortality reduction
falls outside the discussion of economic returns.

16. There is no universally accepted means to place a
monetary value on a life saved
One approach is to use the expected earnings over the
individual’s lifetime.
Another approach is based on comparing wages for risky
occupations to wages elsewhere at similar levels of education
and experience.
A third approach uses the ‘revealed’ behavior of governments:
How much do they spend to reduce mortality?
These approaches give answers that differ by up to 3 orders of
magnitude.
Moreover, they generally place more value on a life in higher
income settings.

17. These last two points should be deal breakers
So, let’s consider saving lives as a human right and take it out of
calculations of economic returns (we have plenty of evidence on
the latter).
This is one area where cost effective analysis succeeds over cost-
benefit approaches.
For example, one can show that the cost per life saved from
community management of acute malnutrition is < clinic based
or that CMAM costs ¼ per life saved compared to a package of
prenatal supplements.
Note: 40% of child mortality is neonatal, another 30% before the
child’s first birthday.

18. Reproducing the Victora curve of WHZ and age
Based on plotting a smoothed curve of a local polynomial regression (the
lpolyci command in STATA v14) with 90% confidence intervals
-.4-.3-.2-.1
0
.1
0 6 12 18 24 30 36 42 48 54 60
Child age (months)
90% CI Girls
90% CI Boys

19. Investing in child nutrition to prevent future chronic
disease
Thirty years ago, David Barker documented a link between
birthweights and adult health.
Since then, epigenetics has provided a mechanism to explain
his fetal origin hypothesis.
Still, reducing chronic disease might provide only 6% of the
total economic benefits of reducing fetal growth restriction.
This reflects the discounting of future benefits [even if nominally
large].
This is also the case for the current limited success of
investments to reduce childhood obesity.

20. Returning to the association of stature
and cognition
There is little dispute that modern economic growth is driven by
skills, not brawn.
So it should be encouraging that at least three recent
systematic reviews of the association of stature and measures
of cognitive development find a regular association.
But overall, this association is weak.
Moreover, this modest association is strongest for the very
young.
If the association is weak as an individual ages, stunting hardly
serves as a proxy for economic objectives.

21. Evidence on the key association of stature and
cognition
For example, one review looked at 12 studies in LMICs that
assessed the association of linear growth with cognitive
development or school outcomes after age 2 years.
Nine of these studies found stronger and more consistent
associations of early linear growth with later cognitive and
school outcomes compared to later linear growth.
Another study found that linear growth through age 12 y was
associated with 0.4–3.4% of the variance in achievement
scores in 4 countries.
Such evidence [and, yes, as always, more research is needed]
has implications for investment priorities over the lifecycle.

22. One implication of this association of stunting and
cognition
Even if improved stunting is not directly causal, addressing early
common determinants affects both outcomes.
If so, stunting rates – or [better] overall stature – would be an easily
tracked indicator of early progress.
Common determinants include overall wealth as well as maternal
education and specific caregiving skills.
A less frequently measured common risk factor is maternal
depression. But there is nascent evidence that there are scalable
means of moderating this risk.
Progress here will not only have an impact on the woman as a
caregiver, but as an individual in her own right.

23. What does the evidence on cognition imply for
priorities after the 1000 days?
There is growing evidence that catch-up growth in stature
occurs after age two, although the measurement of catch-up
remains controversial.
The Young Lives data – a longitudinal set of cohort surveys in
Ethiopia, Andhra Pradesh state in India, Peru, and Viet Nam
with about 2,000 children born in 2001 per country – provides
evidence of changes over a child’s lifetime.
That project shows that some stunted children close height and
cognitive gaps as they age, even without any major changes
in the economic or environmental conditions.

24. Does such evidence on catch-up growth have clear
programmatic implications?
There are only a few studies demonstrating effects of interventions
on linear growth after a child’s second birthday.
There is more evidence from programs that improve cognitive and
social-emotional development after age 2.
Generally, interventions designed to increase stature have a far
smaller impact on cognition than does enhanced stimulation.
But costs and the time line of returns are not well documented.
Also, while there is a risk that promoting physical growth after age 2
can lead to obesity and increase noncommunicable disease, there
is no risk of overdoing cognitive stimulation.
24

25. Human development to 20 years of age

26. Seeking the elusive goal of synergy
Currently, few studies find benefits to integrated nutrition and
child stimulation programs above the sum of individual
program components run independently.
However, there are some promising pilot trials combining
stimulation and complementary feeding such as the
Colombia FAMI program.
Moreover, since there are only a few cases of integration that
reduce independent impacts, there is potential for
streamlined administration that reduces overall costs even
if results are only additive.
26

27. A caveat for any lifecycle nurturing care strategy
Nutrition projects commonly track linear growth either as a
research objective or for monitoring progress.
As with ‘teaching to the exam’, there is a risk that the choice of
outcomes to monitor can influence incentives.
Conversely, while there is less consensus on the optimal tools for
monitoring cognitive development than for measuring stature,
there is an interest in designing tools that can be used widely.
The inclusion of any of such instruments as part of nutritional
assessments will provide opportunities to understand the wider
range of outcomes of investment in nutrition.

28. Addressing equity
While I have stressed lifecycle investments from the viewpoint of
economic growth, they may be more central to equity.
Consider path dependency: Better health [or skills] in one period
creates even higher levels of health [skills] later.
This can explain how a moderate short-term shock can have
long-term impacts.
Relatedly, better health in one period could lead to greater returns
to subsequent child investments, including schooling.
Alternatively, programs in a later period can offset earlier
disparities.

29. An illustration of gaps in cognitive skills
Early Childhood
6-42 months
Middle Childhood 6-8 years
(.000)
(.001)
(.001)
(.082)
(.000)
(.000)
(.000)
(.004)
(.024)
(.566)
(.000)
(.000)
(.002)
(.034)
(.196)
(.999)
-.20.05.1.15.2.25.3.35.4.45.5
Changeinwealthgap
0
.1.2.3.4.5.6.7.8.9
1
Wealthgap
Cognitive Factor Full Scale IQ Achievement
Step 0: Wealth gap Step 1: Add parental Step 2: Add HAZ
Step 3: Add home early Step 4: Add home middle Step 5: Add school

30. Equity considerations
Missed opportunities for child development are costly not merely in terms of
unrealized productivity but also in terms of equity, even across generations.
Economic efficiency implies investing more in children with greater expected
returns, often that is, those with a strong foundation; equity often implies
something different.
Thus, it is noteworthy that many trials (often with home visiting) show that even
if stunting is not reversed, stimulation can close the cognitive gap associated
with early malnutrition.
This was illustrated in a famous longitudinal trial in Jamaica that helped stunted
children catch up to the earnings of a non-stunted comparison group over 20
years.
The challenge: achieve this at scale.

31. Conclusions
Nutrition-specific investments save lives.
Moreover, they often are an economically efficient means to enhance
productivity in low- and middle-income settings.
But this is not automatic. If we want economic impacts we have to fine-
tune design accordingly.
While stature is an indicator of success in many such programs, an over-
emphasis on this indicator can be misleading.
Even under the most optimistic projections for the SDGs, some children
will be stunted at the end of the critical 1000 days. Thus, there is a need
to see that they do not fall into a bad diet trap. Moreover, we need to
ensure that they do not fall further behind in their cognitive potential.