learning, hygiene, and traditional medicine hygiene, and traditional medicine ... introduction...

Learning, Hygiene, and Traditional Medicine

Daniel BennettUniversity of Chicago

Syed Ali Asjad NaqviVienna University of Economics and Business

Wolf-Peter SchmidtLondon School of Hygiene and Tropical Medicine

June 25, 2014

Bennett, Naqvi, and Schmidt (UC, WU, LSHTM) Learning, Hygiene, and Traditional Medicine June 5, 2014 1 / 43

Introduction

Information and health

• Many health behaviors are costly or inconvenient.

• The lack of information may constrain behavior and health.

• Information treatments have mixed effects on sexual behavior, nutrition,malaria prevention, and sanitation.(e.g. De Walque 2007, Madajewicz et al. 2007, Dupas 2011, Luo et al. 2012)

Bayesian learning

• People learn from signals that are (1) novel and (2) credible.

• Infectious disease prevention messages rely on the germ theory of disease.

• Alternative disease models that do not involve invisible pathogens.


Introduction

Unani Medicine

• Foods, objects, and actions have “hot” or “cold” properties.

• People become sick through a hot/cold imbalance.

• Treat illness by readjusting hot/cold exposure.

Diarrhea

• Diarrhea is a leading cause of infant and child mortality.

• Unani medicine: diarrhea is a hot disease. Withhold liquids and foods.

• Modern medicine: oral rehydration therapy.

Crowd-Out

• Traditional and modern medicine may be substitutes.

• Precise priors may make people unreceptive to modern medicine.

• Showing the existence of microbes may make hygiene more plausible.


Outline

Model

• A simple Bayesian learning model.

• Traditional medical beliefs interfere with learning.

• The convenience of hygiene mediates the impact on behavior.

Experiment

• Cluster-randomized trial: Microbe Literacy and Instruction Only treatments.

• Improvements in hygiene knowledge, behavior, and health.

The Role of Traditional Medicine

• ML reduces adherence to traditional medicine.

• Only people without traditional beliefs learn from ML.

• Only non-believers with high hygiene propensities adopt better hygiene.


Model

Setup

• Health is a function of hygiene effort: h(e; ω) = ω ln(e + 1).

• People have priors over ω, the effectiveness of hygiene: ω ∼ N(µ, τ)

• Hygiene education provides a signal, ω ∼ N(µ, τ), of hygiene effectiveness.

Bayesian learning

• People update their beliefs according to Bayes Rule.

µ′ =τ

τ + τµ +

τ

τ + τµ

τ′ = τ + τ


Model

The treatment effect on ω

E [ω1i −ω0

i ] = µ′ − µ

=τ(µ− µ)

τ + τ> 0 if µ > µ

The microscope demonstration

• The microscope demonstration makes the educational signal, τ, more precise.

• A more precise signal increases learning.

∂E [ω1i −ω0

i ]

∂τ=

τ(µ− µ)

(τ + τ)2> 0 if µ > µ


Model

Traditional medical beliefs

• Traditional medicine may increase the precision of the prior, τ.

• A more precise prior decreases learning.

∂E [ω1i −ω0

i ]

∂τ=

τ(µ− µ)

(τ + τ)2< 0 if µ > µ


Model

Hygiene behavior

• Contingent utility u(h, c) = h+ c and budget constraint: pe + c ≤ y .

• maxe µ ln(e + 1) subject to pe + c ≤ y

e∗ =µ

p− 1

The treatment effect on hygiene

E [e1i − e0i ] =τ(µ− µ)

p(τ + τ)> 0 if µ > µ

The complementarity of τ and p

∂E [e1i − e0i ]

∂τ< 0 and

∂E [e1i − e0i ]

∂p< 0 but

∂2E [e1i − e0i ]

∂τ∂p> 0


Setting

Southern Punjab Province

• Four districts with heavy wheat and cotton cultivation.

• 33% of women work outside the home.

Social context

• Communities are Muslim and practice purdah.

• 70% of women “seldom or never” speak with anyone outside the village.

• 83% of women have left the village 0 or 1 times in the past week.

Adult literacy classes

• Free, government-sponsored courses cover basic literacy and numeracy.

• Classes meet six times per week for 90 minutes and last for six months.

• 89% of participants lack formal schooling.

• Classes are gender segregated.


Intervention

Microbe Literacy (ML)

• Participants view bacteria from the environment under a microscope.

• Components: microscope demonstration, infection-prevention workshop.

• Workshops last 90 minutes and occur several days apart.

Microscope Demonstration

• Facilitators use magnifying glasses to demonstrate magnification.

• Facilitators gather samples of everyday substances (e.g. standing water).

• Participants take turns looking through the microscope.

Infection-Prevention Workshop

• Participants learn that invisible pathogens cause disease.

• Facilitators discuss the ways that pathogens can enter our bodies.

• Emphasis on the causes, consequences, and treatment of diarrhea.


Microscope Demonstration


Study

Sample

• We offered ML to students in existing all-female adult literacy classes (ALCs).

• Participants range in age from 15-68. The median age is 25.

Treatment arms

1. “Microbe Literacy” (ML): microscope demo + infection prevention workshop.

2. “Instruction Only” (IO): only the infection prevention workshop.

3. “Control” (C): no programming.

Cluster-randomized trial

• We grouped 210 ALCs into 110 randomization clusters.

• Control ALCs are a median of 2 km from the nearest ML or IO ALC.

• We stratify by diarrhea prevalence and district (12 strata).


Table 1: Baseline Characteristics by Treatment Status

Mean P-valueML IO C ML − IO ML − C(1) (2) (3) (4) (5)

Demographic CharacteristicsAge 26.1 26.1 26.3 0.85 0.92Illiterate 0.20 0.25 0.24 0.30 0.52Any schooling 0.10 0.14 0.08 0.30 0.29Married 0.54 0.54 0.55 0.88 0.76Household size 7.0 6.9 7.1 0.90 0.99Barailvi sect 0.86 0.86 0.82 0.78 0.46Ramadan fasting days 12.1 12.9 11.7 0.40 0.56Prays at least once per day 0.63 0.72 0.71 0.09∗ 0.14Attrition 0.03 0.03 0.04 0.64 0.81

Economic CharacteristicsImproved roof 0.88 0.83 0.81 0.48 0.12Bedrooms 2.2 2.1 2.2 0.19 0.78Any savings 0.12 0.10 0.13 0.54 0.94Land (acres) 3.3 4.0 2.9 0.54 0.60Animals 0.65 0.68 0.68 0.66 0.25Works outside the home 0.29 0.36 0.37 0.23 0.01∗∗∗

Electricity 0.92 0.95 0.93 0.17 0.88Refrigerator 0.28 0.29 0.24 0.83 0.18Mobile phone 0.88 0.82 0.85 0.03∗∗ 0.40Agriculture 0.50 0.48 0.46 0.83 0.94

Note: p-values are based on OLS regressions with clustered standard errors that control for strata dummies.* p < 0.1, ** p < 0.05, *** p < 0.01.


Outcome Variables

Hygiene knowledge

• Four factual questions about communicable disease transmission.

• The knowledge index is the sum of correct responses.

Knowledge items

1. I can tell if my hands are clean just by looking at them. (58% agree)

2. Untreated water is safe to drink. (32% agree)

3. It is safe to eat food that has been touched by flies. (12% agree)

4. The worst thing diarrhea can do is make a child uncomfortable. (86% agree)


Baseline Hygiene Knowledge

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Knowledge Index


Outcome Variables

Hygiene

• Challenge: social desirability bias.

• Self-reported hand washing with soap after defecation and before cooking.

• The appearance of the respondent and her children (Likert scale: 1-3).

Health

• Self-reported prevalence of diarrhea, fever, and cough in the past two weeks.

• Responses for the respondent and her three youngest children.

• Interpreting the definition of “diarrhea”.


Table 1: Baseline Characteristics by Treatment Status

Mean P-valueML IO C ML − IO ML − C(1) (2) (3) (4) (5)

Respondent OutcomesKnowledge score 1.93 2.13 2.18 0.15 0.04∗∗

Traditional Belief Index 2.56 2.68 2.73 0.62 0.94Washes hands after defecation 1.81 1.77 1.79 0.57 0.21Washes hands before cooking 1.67 1.48 1.58 0.06∗ 0.05∗∗

Appearance 2.35 2.37 2.36 0.58 0.61Diarrhea 0.12 0.15 0.14 0.49 0.72Cough 0.17 0.17 0.15 0.59 0.09Fever 0.24 0.27 0.25 0.63 0.52

Child OutcomesAppearance 2.10 2.18 2.15 0.15 0.53Diarrhea 0.31 0.35 0.36 0.55 0.23Cough 0.23 0.22 0.26 0.94 0.95Fever 0.34 0.34 0.40 0.74 0.24

Note: p-values are based on OLS regressions with clustered standard errors that control for strata dummies.* p < 0.1, ** p < 0.05, *** p < 0.01.


Table 2: The Correlation Between Personal and Household Hygiene Measures

Absence of Absence of Clean SoapDefecation Garbage Kitchen Present

(1) (2) (3) (4)

Washes Hands After Defecation 0.19∗∗∗ 0.11∗∗ 0.085∗∗∗ 0.13∗∗∗

(0.064) (0.049) (0.023) (0.024)[0.02] [0.01] [0.01] [0.02]

Washes Hands Before Cooking -0.033 -0.014 0.053∗∗ 0.026(0.050) (0.039) (0.020) (0.022)[0.00] [0.00] [0.01] [0.00]

Appearance of Respondent 0.38∗∗∗ 0.31∗∗∗ 0.40∗∗∗ 0.25∗∗∗

(0.050) (0.040) (0.023) (0.024)[0.08] [0.08] [0.22] [0.09]

Appearance of Children 0.30∗∗∗ 0.22∗∗∗ 0.39∗∗∗ 0.28∗∗∗

(0.052) (0.041) (0.028) (0.026)[0.05] [0.04] [0.19] [0.10]

Note: Each cell reports the coefficient, clustered standard error, and R2 from a simple regression of the column variableon the row variable.


Estimation

Behavior, health, and traditional medical beliefs

Yij = β1MLj + β2IOj + X b ′ij β3 + Sj + εij

• Regression use only follow-up data for respondent i in ALC j .

• ML and IO treatment arms; S strata indicators; X b baseline characteristics.

• Standard errors are clustered by randomization group.

Hygiene knowledge

Yijt = β1[POSTt ·MLj ] + β2[POSTt · IOj ]

+ β3MLj + β4IOj + β5POSTt + Sj + εijt

• Address the baseline knowledge imbalance through a difference-in-difference.


Table 3: The Impact of Hygiene Education on Hygiene Knowledge

Dependent variable: Score Q1 Q2 Q3 Q4(1) (2) (3) (4) (5)

Post · Microbe Literacy 0.28∗∗∗ -0.11∗∗ -0.11∗∗ -0.013 -0.046∗

(0.086) (0.054) (0.057) (0.035) (0.027)

Post · Instruction Only 0.11 -0.045 -0.025 -0.026 -0.0091(0.091) (0.055) (0.050) (0.031) (0.033)

Post · ML − Post · IO (p-value) 0.07 0.23 0.10 0.72 0.23

Dependent variable mean 2.05 0.70 0.23 0.08 0.92Observations 7516 7516 7516 7516 7516

Note: standard errors, which appear in parentheses, are clustered by randomization group. All regressionscontrol for strata dummies. Q1: “I can tell that my hands are clean just by looking at them”; Q2: “Untreatedwater is safe to drink”; Q3: “It is safe to eat food that has been touched by flies”; Q4: “The worst thing diarrheacan do is make a child uncomfortable.” * p < 0.1, ** p < 0.05, *** p < 0.01.


Table 3: The Impact of Hygiene Education on Hygiene Knowledge

Dependent variable: Score Q1 Q2 Q3 Q4(1) (2) (3) (4) (5)

Post · Microbe Literacy 0.28∗∗∗ -0.11∗∗ -0.11∗∗ -0.013 -0.046∗

(0.086) (0.054) (0.057) (0.035) (0.027)

Post · Instruction Only 0.11 -0.045 -0.025 -0.026 -0.0091(0.091) (0.055) (0.050) (0.031) (0.033)

Post · ML − Post · IO (p-value) 0.07 0.23 0.10 0.72 0.23


Note: standard errors, which appear in parentheses, are clustered by randomization group. All regressionscontrol for strata dummies. Q1: “I can tell that my hands are clean just by looking at them”; Q2: “Untreatedwater is safe to drink”; Q3: “It is safe to eat food that has been touched by flies”; Q4: “The worst thing diarrheacan do is make a child uncomfortable.” * p < 0.1, ** p < 0.05, *** p < 0.01.


Table 4: The Impact on Hygiene

Depdendent variable: Hand Washing AppearanceDefecation Cooking R C

(1) (2) (3) (4)

Microbe Literacy 0.057 0.043 0.16∗∗ 0.096(0.036) (0.047) (0.068) (0.065)

Infection Prevention 0.042 -0.024 0.063 0.10∗

(0.039) (0.051) (0.056) (0.058)

ML − IO (p-value) 0.60 0.36 0.11 0.93

Dependent variable mean 1.86 1.68 2.33 1.96Observations 3704 3482 3704 2714

Note: standard errors, which appear in parentheses, are clustered by randomization group. Allregressions control for strata dummies. * p < 0.1, ** p < 0.05, *** p < 0.01.


Table 5: The Impact of Hygiene Education on Health

Dependent variable: Diarrhea Cough FeverSample: R C R C R C

(1) (2) (3) (4) (5) (6)

Microbe Literacy -0.029 -0.021 -0.056∗∗∗ -0.043∗∗ -0.12∗∗∗ -0.055(0.022) (0.033) (0.017) (0.021) (0.038) (0.036)

Instruction Only -0.0047 0.010 0.0099 -0.0050 -0.068∗ -0.057(0.024) (0.033) (0.021) (0.022) (0.039) (0.036)

ML − IO (p-value) 0.23 0.35 0.00 0.06 0.13 0.96

Dependent variable mean 0.11 0.21 0.13 0.13 0.26 0.27Observations 3836 2619 3836 2619 3836 2619

Note: standard errors, which appear in parentheses, are clustered by randomization group. Odd columns show results forthe respondent and even columns show results for her children under age 5. All regressions control for strata dummies.* p < 0.1, ** p < 0.05, *** p < 0.01.


Traditional Medical Beliefs

Unani Medicine

• Imbalance between “hot” and “cold” elements causes disease.

• Treat diarrhea by withholding certain foods and liquids.

• Hakims provide traditional medical advice and treatment.

Traditional Belief Index (TBI)

• Main: beliefs in hot/cold, withholding liquids and foods, home remedies.

• Narrow: only beliefs in hot/cold.

• Broad: add traditional medical utilization.

Key Items

• Does eating hot or cold foods causes diarrhea?

• Is withholding liquids or breast milk an effective treatment for diarrhea?

• Have you consulted a hakim in the past three months?

• Would you see a hakim if your child was having seizures or fainting?


Traditional Medical Beliefs

0

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Traditional Belief Index


Table 6: The Impact of Hygiene Education on Traditional Medical Beliefs

Diarrhea Causes Diarrhea TreatmentsTBI Hot Foods Cold Foods No Food No Milk(1) (2) (3) (4) (5)

Microbe Literacy -0.23∗∗ 0.020 -0.036 -0.057∗∗ -0.062∗∗

(0.11) (0.018) (0.029) (0.027) (0.028)

Instruction Only 0.0025 0.00026 -0.039 -0.00012 -0.035(0.13) (0.019) (0.032) (0.037) (0.035)

ML − IO (p-value) 0.05 0.26 0.92 0.07 0.42


Note: standard errors, which appear in parentheses, are clustered by randomization group. All regressions control forstrata dummies. * p < 0.1, ** p < 0.05, *** p < 0.01.


0

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ML Control Bennett, Naqvi, and Schmidt (UC, WU, LSHTM) Learning, Hygiene, and Traditional Medicine June 5, 2014 31 / 43

Interaction with Traditional Medical Beliefs

Hypothesis

• Traditional beliefs imply precise priors, which weaken the treatment effect.

Estimation

• Interact ML and IO with the TBI or indicators for TBIH and TBIL.

• The TBI may be correlated with mediating factors: e.g. SES, cognitive ability.

• Control for the interaction of treatment with demographic, economic,hygiene, and health variables, which may be correlated with the TBI.


Table 7: Baseline Characteristics of Respondents by TBI

MeanTBI ≤ 2 TBI > 2

(1) (2)

Demographic CharacteristicsAge 25.6 26.8∗

Illiterate 0.20 0.27Any schooling 0.11 0.11Married 0.52 0.57Household size 6.8 7.2∗∗

Barailvi sect 0.83 0.86∗∗

Ramadan fasting days 12.5 12.0Prays at least once per day 0.67 0.70

Economic CharacteristicsImproved roof 0.86 0.81Bedrooms 2.17 2.18Any savings 0.08 0.15∗∗∗

Land (acres) 3.3 3.6Animals 0.68 0.66Works outside the home 0.38 0.30Electricity 0.93 0.94Refrigerator 0.28 0.26Mobile phone 0.86 0.84∗∗

Agriculture 0.50 0.46

Note: p-values in Column 2 are based on OLS regressions with clus-tered standard errors. * p < 0.1, ** p < 0.05, *** p < 0.01.


Table 7: Baseline Characteristics of Respondents by TBI

MeanTBI ≤ 2 TBI > 2

(1) (2)

Respondent OutcomesKnowledge score 2.14 2.01∗∗

Washes hands after defecation 1.80 1.78Washes hands before cooking 1.57 1.58Appearance 2.34 2.39Diarrhea 0.12 0.16Cough 0.16 0.18Fever 0.25 0.26

Child OutcomesAppearance 2.12 2.17Diarrhea 0.33 0.35Cough 0.23 0.25Fever 0.34 0.38

Note: p-values in Column 2 are based on OLS regressions with clus-tered standard errors. * p < 0.1, ** p < 0.05, *** p < 0.01.


Table 8: The Interaction Between Microbe Literacy and Traditional Beliefs for Hygiene Knowledge

Dependent variable: Knowledge Index(1) (2) (3) (4) (5)

Panel A: TBI InteractionPost · ML 0.72∗∗∗ 0.64∗∗∗ 0.71∗∗∗ 0.73∗∗ 1.01∗∗∗

(0.23) (0.23) (0.22) (0.35) (0.34)

Post · ML · TBI -0.17∗∗ -0.28 -0.16∗∗ -0.16∗∗ -0.15∗

(0.079) (0.17) (0.069) (0.075) (0.076)

Panel B: By High and Low TBI

Post · ML · TBIL 0.38∗∗∗ 0.31∗∗∗ 0.42∗∗∗ 0.50∗ 0.53∗∗

(0.12) (0.090) (0.12) (0.27) (0.26)

Post · ML · TBIH 0.12 0.063 0.11 0.21 0.28(0.10) (0.16) (0.10) (0.27) (0.24)

Post · Treatment:· Demo. and Economic Controls - - - Yes -· Hygiene and Health Controls - - - - Yes

Traditional Belief Index Main Narrow Broad Main MainObservations 7516 7516 7516 7516 7516

Note: standard errors, which appear in parentheses, are clustered by randomization group. All regressions include stratadummies and levels and interactions for IO, Post, and TBI. Demographic and economic controls appear in Table 1. Hygieneand health controls include the baseline appearance, diarrhea, fever, and cough for the respondent and her children under age5. In Panel B, we cut the TBI at the median of 2. * p < 0.1, ** p < 0.05, *** p < 0.01.





(0.23) (0.23) (0.22) (0.35) (0.34)

Post · ML · TBI -0.17∗∗ -0.28 -0.16∗∗ -0.16∗∗ -0.15∗

(0.079) (0.17) (0.069) (0.075) (0.076)


Post · ML · TBIL 0.38∗∗∗ 0.31∗∗∗ 0.42∗∗∗ 0.50∗ 0.53∗∗

(0.12) (0.090) (0.12) (0.27) (0.26)

Post · ML · TBIH 0.12 0.063 0.11 0.21 0.28(0.10) (0.16) (0.10) (0.27) (0.24)





Traditional Beliefs and Learning

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

≤1 2 3 ≥4

Co

eff

icie

nt


Absolute Effect of ML Differential Effect of ML


The Interaction with Hygiene Propensities

Predictions

• The treatment effect on behavior and health should be the strongest forpeople with low values of both τ and p.

Estimation

• Estimate a hygiene propensity score with baseline data.

• Isolate respondents with high hygiene propensities.

• Regressors: house type, roof type, food insecurity, age, religious adherence,latrine characteristics, water source characteristics, presence of animals.

• Dummy variables for all categorical responses.

• R2 ≈ 0.10.


Hygiene and Hygiene Propensity


Table 9: The Interaction Between Microbe Literacy and Traditional Beliefs for Hygiene and Health

Respondent ChildrenAppearance Health Appearance Health

(1) (2) (3) (4) (5) (6) (7) (8)

Panel A: TBI InteractionML 0.34∗∗ 0.40∗∗∗ 0.32∗∗ 0.35∗∗ 0.15 0.17 0.28∗∗ 0.29∗∗

(0.13) (0.13) (0.15) (0.14) (0.12) (0.12) (0.13) (0.13)

ML · TBI -0.074∗ -0.098∗∗ -0.048 -0.054 -0.021 -0.033 -0.058 -0.063(0.042) (0.042) (0.048) (0.052) (0.040) (0.041) (0.041) (0.042)

Panel B: By High and Low TBIML · TBIL 0.24∗∗∗ 0.28∗∗∗ 0.26∗∗∗ 0.28∗∗∗ 0.13∗ 0.12 0.14∗∗ 0.14∗∗

(0.079) (0.085) (0.084) (0.079) (0.073) (0.075) (0.068) (0.067)

ML · TBIH 0.079 0.070 0.14∗∗ 0.15∗∗ 0.066 0.054 0.12∗∗ 0.12∗∗

(0.059) (0.063) (0.063) (0.068) (0.066) (0.066) (0.052) (0.051)

ML · TBIL − ML · TBIH (p-value) 0.02 0.01 0.10 0.11 0.30 0.35 0.77 0.75

Sample Full HP Full HP Full HP Full HPObservations 3836 2008 3836 2008 2823 2640 5696 5278

Note: standard errors, which appear in parentheses, are clustered by randomization group. All regressions include strata dummies and levels and interactionsof ML, IO, and TBI. In Panel B, we cut the TBI at the median of 2. Even columns show results for respondents with above-median hygiene propensities. *p < 0.1, ** p < 0.05, *** p < 0.01.


Hygiene Behavior by TBI and Propensity Score

-0.2

-0.1

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

≤1 2 3 ≥4

Mic

rob

e L

itera

cy

Co

eff

icie

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High Hygiene Propensity Low Hygiene Propensity


Conclusion

Impact evaluation

• The microscope demonstration improves learning, hygiene, and health.

• Stronger results for the respondent than for her children.

• 2nd follow-up (August): impact decay, intra-household spillovers.

Traditional medicine

• ML reduces reduces adherence to traditional medicine.

• People with strong beliefs benefit less from the program.

• Implication: traditional medicine may contribute to infectious disease.

Informational interventions

• The extended causal chain from knowledge to health.

• Investments may be more cost-effective.


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