Mental models risk communication to promote private well testing in underserved minority communities

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Frank Stillo III1; Erica Wood1; Wändi Bruine de Bruin2; Catherine Zimmer3; Jacqueline MacDonald Gibson1

1University of North Carolina at Chapel Hill, Gillings School of Global Public Health2Leeds University Business School, Behavioural Decision Research

3University of North Carolina at Chapel Hill, Odum Institute for Research in Social Science

November 1, 2018

Some Private Well Owners Are Surrounded by Municipal Water Supplies

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Private Water Systems

• No monitoring requirements for residents

• Residents must rely on their own technical expertise

• Residents responsible for cost of testing and maintenance of water source

Source: Stillo et. al. 2017

Annually

Every 2-3 years

Every 4-5 years

Every 6-10 years

>10 years

Never

Other/ unspecified

0 1 2 3 4 5

Recommended Testing Frequencies

Bacteria: Annually

Inorganics (Lead, Copper): 2 years

Volatile organic compounds and Pesticides: 5 years

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Homeowners Do Not Follow Recommended Testing Frequencies

Source: Fizer et. al. 2017

Testing Frequency of Homeowners

Research Objective

• Identify homeowner perceptions and knowledge gaps influencing private well owner decisions to test or not test their water quality– Focus on majority African American in peri-urban communities of Wake

County, NC, in close proximity to municipal water services

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Methods

1. Identify what people need to know to make more informed decisions.

2. Identify what people already know and how they make their decisions.

3. Design communication content.

4. Test effectiveness of communication content.

We Used the Mental Models Approach to Risk Communication

Source: Bruine de Bruin and Granger et. al. 2013

Step 1: Identify What People Need to Know by Building Influence Diagram with Experts

We completed Step 1 in prior research.

Two-Step Process

• Two-part process:a. Semi-structured interviews

– Open-ended conversations regarding the main topics of the expert model

– Compare results to expert model

b. Population survey– Prevalence of common misperceptions and knowledge gaps

identified in interviews

• Part a completed in prior research

Step 2: Identify What People Already Know and How They Make Decisions

Step 2, Part a, Revealed Gaps Between Expert Model and Lay Beliefs

Example: People do not know what to test for or how often.

Survey Topics:

1. Water Testing

2. Costs

3. Well Maintenance

4. Septic Systems

5. Pollution Sources

6. Water and Health

7. Water Quality Perceptions

8. Demographics

Step 2, part b: Administer Population Survey to Determine Knowledge, Beliefs Driving Decisions

3. Design the risk communication intervention to target key knowledge, beliefs affecting behavior

4. Test via a randomized-controlled trial

Steps 3 and 4 Design and Test an Intervention

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Results

Demographic Survey Study Participants

Male/ Female (n=71) 37% / 63%

Median participant age 64

Race (n=73)

African-American 53%

White 38%

Asian/Asian American 1.4%

Other 6.8%

Education (n=71)

Less than high school 13%

High school or GED 13%

Some college to

Bachelor's degree54%

Graduate school 21%

Median Household

Income62,000

Median age of well 35 years13

Characteristics of study participants and their wells (n=76)

• Majority African American

• Educated population

• Income slightly above the county average

• Old Wells

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Few Survey Respondents Tested Their Water at the Frequencies Recommended by Health Departments

0.0%

10.0%

20.0%

30.0%

40.0%

50.0%

60.0%

70.0%

One Year Two Years Five Years Ten Years

Pe

rce

nta

ge o

f H

om

es

Test

ing

Private Well Water Testing Frequency

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Three Factors and Well Age Predict Water Testing

SensoryPerceptions

Lack of Knowledge

andUrgency

Well Age

CostBarrier

Water Testedwithin Past

2 Years

r =

0.2

49

*

Exp(β) = 0.430**Exp(β) = 0.582**

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Non-Testers Believe They Can “Sense” Contaminants

Factored QuestionsTested:

M(SD)

Non-Testers:

M (SD)

Factor 1: Sensory Perception Misconception 0.98 (1.07)** 1.68 (1.40)**

Water looks, smells, and tastes fine, so there is no

need to test 1.33 (1.32)* 1.78 (1.46)

No need to test, been using the water for years

without problems 0.71 (1.06)** 1.60 (1.55)**

My well water does not need to be tested because

it looks clear, has no smell, and tastes clean 0.90 (1.14)* 1.67 (1.54)*

*p ≤ 0.05; ** p ≤ 0.01

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Non-Testers Don’t Know How to Test, Don’t Prioritize Testing

Factored QuestionsTested:

M(SD)

Non-Testers:

M (SD)

Factor 2: Lack of Knowledge and Urgency to Test 1.13 (1.15)** 2.12(1.11)**

Plan to test but haven’t gotten around to it. 1.52 (1.54)* 2.12 (1.11)**

No time to test 0.67 (1.02)* 1.25 (1.19)*

Don’t know where to test for 0.95 (1.47)* 1.69 (1.53)*

Don’t know how to test for 0.95 (1.47)* 1.74 (1.57)*

Don’t know what to test for 1.19 (1.60)** 2.19 (1.46)**

Wouldn’t know what to do if failed test 1.52 (1.67)* 2.33 (1.53)*

*p ≤ 0.05; ** p ≤ 0.01

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Cost Is a Barrier to Testing

Factored QuestionsTested:

M(SD)

Non-Testers:

M (SD)

Factor 3: Cost Barrier to Testing1.37(0.95)** 2.14(1.01)**

I couldn’t afford the cost of testing my well water. 0.81 (1.36)** 1.93 (1.45)**

I couldn’t afford to fix my well water if

contaminated with bacteria.1.00 (1.30)** 1.91 (1.53)**

I couldn’t afford to fix my well water if

contaminated with chemicals. 1.05 (1.24)** 2.19 (1.51)**

I would prefer to drink city water if it were free. 1.52 (1.29) 1.65 (1.47)

Getting water from a well is free. 1.76 (1.37)** 2.60 (1.41)**

I would install a home water filter if I could afford

it. 2.39 (1.42) 2.63 (1.24)

*p ≤ 0.05; ** p ≤ 0.01

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Results Informed the Design of a Risk Communication

Residents are unaware or unsure about their water

quality and who to contact to help

Right up front, we encourage a sense of

URGENCY

Using sensory perceptions to indicate when to test or to identify a problem

is common misconception

Wood et. al., in preparation

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Results Informed Risk Communication Deisgn

Easy 2 step directions remove this barrier (how to

test) and make it urgent.

Since we also offer free testing, we wanted residents to know

discounted rates may be available

Offering FREE helpwas found to

influence testing and removed the “Now

what do I do” barrier.

Residents were unaware of testing frequency and which contaminants are

important

Wood et. al., in preparation

Randomized Controlled Trial Design

Financial Intervention Behavioral (Risk Communication) InterventionNo Risk Communication

Risk Communication

No Free Water Test Group 1 (control) Group 2

Free Water Test Group 3 Group 4

Ongoing Randomized-Controlled Trial Is Testing the Communication and Role of Cost

Conclusions

• Risk communications should

– emphasize correcting misconceptions that can contaminants be detected through sensory perception

– provide clear information about how and where to get water tested

• Subsidies or free testing could help increase testing rates

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Acknowledgments

Co-AuthorsDr. Jackie MacDonald GibsonDr. Wändi Bruine de BruinDr. Catherine ZimmerErica Wood

FundingWater Resource Research Institute (WRRI) and NC Sea Grant Student Fellowship

EPA STAR Grant

NC Policy Collaborative

MacDonald Gibson Research TeamCeleste Carberry, Sara Colley, Abhishek Komandur, Sydney Lockhart, Zahra Al Hamdani, Ally Clonch, Walker Grimshaw, Riley Mulhern and many others!