Variables  Variable Description
1. Census tract variables  
Poverty ≥ 20% vs< 20% of households with income below the federal poverty level
Education ≥ 25% vs< 25% of adults with less than a high school education
Residence area grouped using Beale codes: 100% rural; urban-rural mix; 100% urban
Employment  ≥ 66% versus < 66% of population aged 16 and over who are unemployed
2. Demographic variables  
Insurance no insurance; Medicaid; Medicare and public; private insurance
Marital status single-never married; married; separated; widowed; divorced; unknown
Age  age at diagnosis
3. Tumor characteristics  
Stage regional; distant; localized
Grade moderately differentiate; poorly/un-differentiate; well differentiate; unknown
Tumor size < 1cm; 1:1 ~ 2cm; 2:1 ~ 3cm; > 3cm; unknown
Comorbidity mild; moderate; severe; none; unknown
4. Treatment indicators  
Surgery mastectomy, lumpectomy, no surgery
Radiation  not administered; administered
Chemotherapy  not administered, administered
Hormonal therapy not administered; administered
ER/PR receptor either is positive; both are negative; unknown
Table 1: Potential Mediators in the Motivating Example.