Claims data comes from FEMA (will update to OpenFEMA claims dataset v2), and goes from 1978 - 2012. Geography of claims data is 2010 Census Tract boundaries. Census data comes from Longitudinal Tract Database (Brown University), which provides interpolated data between historical census results and 2010 census tract boundaries; estimates are based on the documented population and household counts.
Current filters:
Total claims records after filtering: 1139833
Base Model:
\(Y\) is the outcome variable, depending on research questions:
\(X\) is independent variable of interest (i.e. measures of income, wealth, race). The rest of the base model variables are claims-level characteristics that account for flood event severity and damage: \(damage\) is the ratio between assessed damage / property value (omitted when either component value is included); \(waterdepth\) is the recorded depth of floodwater; \(duration\) is the length of the flooding event; \(cat\) is the indicator that the claim is associated with a catastrophe. The final covariate is an indicator if the claim was reopened during processing (\(reopen\)).
Model includes State Fixed Effects (\(i\)) + Year Fixed Effects (\(t\)).
\[log(Y) = \beta_{0} + \beta_{1}X + \beta_{2}(damage) + \beta_{3}(waterdepth) + \beta_{4}(duration)_{it} + \beta_{5}(cat) + \beta_{6}(reopen) + StateFE_{t} + YearFE_{i} u_{it}\]
Full Model:
Base Model, plus two additional sets of covariates:
\[log(Y) = \beta_{0} + \beta_{1}X + \beta_{2}(damage) + \beta_{3}(waterdepth) + \beta_{4}(duration)_{it} + \beta_{4}(cat) + \beta_{6}(reopen) + \theta_{it} + \gamma_{it} + StateFE_{t} + YearFE_{i} u_{it}\]
All independent variables are standardized for easier comparison.
Standard errors are clustered at the state level (see Appendix for base model result comparisons with several SE clustering approaches. ). Some references for SE cluster identification:
Correlation Check of Variables
A check of the correlation across covariates validates our approach to model structure: there is high collinearity between census variables of income, wealth, and race, such that separate models and interaction effects will be necessary. There is low collinearity between our claims variables. Monthly claim volume is correlated with damage, and catastrophe indicator, such that we should consider omitting one or the other. Notably, there is little correlation between the claim-level property value, and tract-level wealth and income variables - including median home value.
Percent Total claims records after filtering: 71%
Using several measures of income (median HH income, poverty, and income buckets), we can see a small but statistically positive relationship between income and claims processing time, meaning that claims from higher-income tracts tend to take longer to resolve. Income Model 1 shows us that with one standard deviation increase in census tract income, there is about a 4% increase in claim processing time. That is consistent with Model 2 results, which show the effect of income on claims time based on income quantiles (compared to reference group of $ 100 - 150,000 med income). The relationship between the amount of households in poverty and claims processing is negative, suggesting a similar relationship.
Because there may be a difference between the impact of income and wealth, we look separately at factors that indicate household wealth. While we do not have perfect census measures of wealth, property ownership, educational attainment, and property value (as assessed by insurer at the property level, and in Census at tract level) may be a sufficient proxy for wealth and class separate from income (see Chetty et al 2019 as examples indicators of wealth within ACS data). Here we see a negligible effect of homeownership and property value on claims processing time. Educational attainment (measured by the percent of population with a college degree) has a statistically significant positive relationship with claims processing time.
There is high correlation between median income and percent owners, population by race, and education levels of tract data, so they are not used as covariates together in models. Instead, we estimate separate models looking at the effect of race, interacted with income categories, to understand how the claims processing time differs for tracts with different demographics. Here, we see that overall, tracts with higher percentage of white population is associated with longer claims processing time, and tracts with higher percentage Black population are associated with shorter claims processing time; there is no statistically significant effect of the percentage of hispanic population.
However, that effect varies by income. In tracts at the lowest income brackets, tracts with a higher percentage of Black population are actually associated with longer claims process times. Compared to other low-income census tracts, 1 standard deviation increase in the percent of black population in tract is associated with > 10% increase in estimated claims processing time.
Percent Total claims records after filtering: 74%
Claims payment measured as the percent of recorded damage actually paid by insurer: the ratio of total payment (including deductible) / assessed damage.
We see little statistically significant relationship between several measures of income and claims payment (relative to damage). Notably, tracts with higher college educated populations are associated with higher claims payment.
Generally, the racial demographics of the census tract are not associated with claims amount. The exception here are tracts with higher Black population: those tracts experienced statistically significant lower claims payment ratios. That effect does seem to vary by income bracket, as tracts with high Black population have relatively higher claims amount ratios compared to that baseline mean.
Many claims in the insurance claims record (~ 23%) are closed without payment. Here, we consider any claims that are either labeled as “CWOP” in claims status, or labeled as “closed” but resulting in $0 claim payment, and the assessed value of damage exceeds the deductible.
There appears to be no effect of income on the likelihood of a claim being closed without payment. Indicators of wealth show a similar story: homeownership and education are not strongly correlated, but college education rates in a census tract is associated with a higher likelihood of a claim being closed without payment.
There does not appear to be any statistically significant relationship between race and income of a tract, and the likelihood of a claim being closed without payment.
| ## Fixed Effects |
| ### State and Year on Median Income |
| # Further Analysis |
| * Incident-specific dynamics (i.e. Hurricane) * County fixed effects? * Other dependent variables to test: + Usage or denials of ICC |
Outcome variable is time between claim submitted and claim closed, measured in days. Because it is count data (integer, non-negative, with long tails) it would typically be a Poisson distribution. However, the assumption for Poisson distribution that the mean = variance is clearly not true for this data (see Table 1 below), suggesting overdispersion of the data.
| mean | median | min | max | variance |
|---|---|---|---|---|
| 62 | 49 | 0 | 296 | 2865 |
A quick test on the basic model, Poisson, shows high overdispersion (well above the threshold of 1).
##
## Overdispersion test
##
## data: tm_p
## z = 402.63, p-value < 2.2e-16
## alternative hypothesis: true dispersion is greater than 1
## sample estimates:
## dispersion
## 46.4318
Applying a negative binomial regression model (which does not assume mean and variance are equal) is a common model for such real-world count data. Comparison of model fit of basic model structure through AIC (lower relative value suggests better fit) indicates that Negative Binomial model is best structure. Note: models tested is basic model structure without Fixed Effects; fixed effects will not impact AIC.
| OLS | Poisson | Negative Binomial | |||||||
| asinh(days) | days | days | |||||||
| Constant | 4 | . | 206*** | 4 | . | 125*** | 4 | . | 121*** |
| (0 | . | 002) | (0 | . | 000) | (0 | . | 001) | |
| Median Income (thousands) | 0 | . | 109*** | 0 | . | 050*** | 0 | . | 059*** |
| (0 | . | 002) | (0 | . | 000) | (0 | . | 001) | |
| Depth of Water | 0 | . | 154*** | 0 | . | 042*** | 0 | . | 041*** |
| (0 | . | 002) | (0 | . | 000) | (0 | . | 001) | |
| Damage as Percent of Prop Value | 0 | . | 031*** | 0 | . | 018*** | 0 | . | 071*** |
| (0 | . | 002) | (0 | . | 000) | (0 | . | 001) | |
| Monthly Claims in Tract | 0 | . | 142*** | 0 | . | 099*** | 0 | . | 101*** |
| (0 | . | 002) | (0 | . | 000) | (0 | . | 001) | |
| AIC | 2865728 | . | 295 | 36774751 | . | 064 | 7964668 | . | 071 |
| p | 0 | . | 000 | 0 | . | 000 | 0 | . | 000 |
| N | 776096 | 776096 | 776096 | ||||||
|
Significance: *** = p < 0.001; ** = p < 0.01; * = p < 0.05 |
|||||||||
Income Effects on Claims Processing
| IM 1 | IM 1 (full) | IM 2 | IM 2 (full) | IM 3 | IM 3 (full) | |
|---|---|---|---|---|---|---|
| Med Income ($thous) | 0.036*** | 0.039*** | ||||
| Income: <35 | -0.112*** | -0.124*** | ||||
| Income: 35-50 | -0.095*** | -0.102*** | ||||
| Income: 50-75 | -0.048** | -0.055*** | ||||
| Income: 75-100 | -0.025 | -0.027+ | ||||
| Income: >150 | 0.071* | 0.074** | ||||
| Pct Poverty | -0.024*** | -0.026*** | ||||
| Flood depth | 0.056*** | 0.056*** | 0.056*** | 0.056*** | 0.056*** | 0.056*** |
| Damage | 0.043 | 0.044 | 0.043 | 0.044 | 0.042 | 0.042 |
| Flood duration | 0.026*** | 0.026*** | 0.026*** | 0.026*** | 0.026*** | 0.026*** |
| Reopened | 0.740*** | 0.742*** | 0.740*** | 0.742*** | 0.741*** | 0.743*** |
| Catastrophe | 0.093*** | 0.089*** | 0.093*** | 0.088*** | 0.094*** | 0.089*** |
| SFHA zone | 0.023 | 0.022 | 0.021 | |||
| Elevated | 0.058** | 0.058** | 0.057** | |||
| Floodproofed | -0.195*** | -0.192** | -0.195*** | |||
| Population | -0.021*** | -0.022*** | -0.020*** | |||
| R2 | 0.011 | 0.011 | 0.011 | 0.011 | 0.011 | 0.011 |
| + p < 0.1, * p < 0.05, ** p < 0.01, *** p < 0.001 | ||||||
Wealth Effects on Claims Processing
| WM 1 | WM 1 (full) | WM 2 | WM 2 (full) | WM 3 | WM 3 (full) | |
|---|---|---|---|---|---|---|
| Property value | 0.001 | 0.001 | ||||
| Homeowners | 0.008** | 0.007** | ||||
| College Educated | 0.039*** | 0.040*** | ||||
| Flood depth | 0.058*** | 0.058*** | 0.058*** | 0.058*** | 0.058*** | 0.059*** |
| Flood duration | 0.026*** | 0.026*** | 0.026*** | 0.026*** | 0.027*** | 0.026*** |
| Reopened | 0.746*** | 0.748*** | 0.746*** | 0.748*** | 0.745*** | 0.747*** |
| Catastrophe | 0.111*** | 0.107*** | 0.111*** | 0.107*** | 0.106*** | 0.102*** |
| SFHA zone | 0.025 | 0.025 | 0.028+ | |||
| Elevated | 0.051** | 0.051** | 0.053** | |||
| Floodproofed | -0.217*** | -0.214*** | -0.240*** | |||
| Population | -0.019*** | -0.020*** | -0.017*** | |||
| R2 | 0.011 | 0.011 | 0.011 | 0.011 | 0.011 | 0.011 |
| + p < 0.1, * p < 0.05, ** p < 0.01, *** p < 0.001 | ||||||
Race & Income Effects on Claims Processing
| R&IM 1 | R&IM 1 (full) | R&IM 2 | R&IM 2 (full) | R&IM 3 | R&IM 3 (full) | |
|---|---|---|---|---|---|---|
| Percent white | 0.028*** | 0.052* | ||||
| Percent black | -0.024*** | -0.122*** | ||||
| Percent hispanic | -0.014*** | 0.014 | ||||
| Race*Income: <35 | -0.044+ | 0.116** | -0.016 | |||
| Race*Income: 35-50 | -0.032 | 0.098** | -0.010 | |||
| Race*Income: 50-75 | -0.016 | 0.094** | -0.037 | |||
| Race*Income: 75-100 | 0.005 | 0.052+ | -0.048 | |||
| Race*Income: >150 | 0.046 | -0.138** | 0.062+ | |||
| Flood depth | 0.055*** | 0.056*** | 0.055*** | 0.056*** | 0.056*** | 0.057*** |
| Damage | 0.041 | 0.041 | 0.042 | 0.043 | 0.040 | 0.040 |
| Flood duration | 0.025*** | 0.025*** | 0.025*** | 0.025*** | 0.025*** | 0.025*** |
| Reopened | 0.741*** | 0.743*** | 0.741*** | 0.742*** | 0.741*** | 0.743*** |
| Catastrophe | 0.099*** | 0.095*** | 0.097*** | 0.092*** | 0.099*** | 0.095*** |
| SFHA zone | 0.024 | 0.023 | 0.022 | |||
| Elevated | 0.048* | 0.052* | 0.052* | |||
| Floodproofed | -0.215*** | -0.201*** | -0.207*** | |||
| Population | -0.016*** | -0.018*** | -0.018*** | |||
| R2 | 0.011 | 0.011 | 0.011 | 0.011 | 0.011 | 0.011 |
| + p < 0.1, * p < 0.05, ** p < 0.01, *** p < 0.001 | ||||||
Income Effects on Claims Amount
| IM 1 | IM 1 (full) | IM 2 | IM 2 (full) | IM 3 | IM 3 (full) | |
|---|---|---|---|---|---|---|
| Med Income ($thous) | 0.246 | 0.240 | ||||
| Income: <35 | -1.108 | -1.065 | ||||
| Income: 35-50 | -1.327* | -1.274+ | ||||
| Income: 50-75 | -1.020+ | -1.005+ | ||||
| Income: 75-100 | -1.160+ | -1.148+ | ||||
| Income: >150 | -1.732 | -1.694 | ||||
| Pct Poverty | -0.147 | -0.131 | ||||
| Flood depth | -0.282*** | -0.291*** | -0.284*** | -0.292*** | -0.281*** | -0.289*** |
| Flood duration | -0.055+ | -0.063+ | -0.056* | -0.064* | -0.054+ | -0.062* |
| Reopened | -0.128 | -0.144 | -0.124 | -0.135 | -0.118 | -0.133 |
| Catastrophe | 0.198 | 0.169 | 0.194 | 0.166 | 0.222 | 0.197 |
| SFHA zone | 0.597* | 0.586* | 0.588* | |||
| Elevated | -0.796*** | -0.798*** | -0.817*** | |||
| Floodproofed | -2.484*** | -2.339*** | -2.444*** | |||
| Population | -0.106 | -0.092 | -0.101 | |||
| R2 | 0.087 | 0.096 | 0.093 | 0.102 | 0.083 | 0.092 |
| + p < 0.1, * p < 0.05, ** p < 0.01, *** p < 0.001 | ||||||
Wealth Effects on Claims Amount
| WM 1 | WM 1 (full) | WM 2 | WM 2 (full) | WM 3 | WM 3 (full) | |
|---|---|---|---|---|---|---|
| Property value | -0.045** | -0.047** | ||||
| Homeowners | -0.062 | -0.070 | ||||
| College Educated | 0.372** | 0.375** | ||||
| Flood depth | -0.282*** | -0.290*** | -0.281*** | -0.289*** | -0.286*** | -0.294*** |
| Flood duration | -0.056+ | -0.063* | -0.055+ | -0.061+ | -0.050+ | -0.055+ |
| Reopened | -0.113 | -0.126 | -0.111 | -0.122 | -0.155 | -0.166 |
| Catastrophe | 0.244+ | 0.217 | 0.240+ | 0.214 | 0.183 | 0.153 |
| SFHA zone | 0.590* | 0.594* | 0.615* | |||
| Elevated | -0.837*** | -0.836*** | -0.808*** | |||
| Floodproofed | -2.421*** | -2.416*** | -2.549*** | |||
| Population | -0.103 | -0.102 | -0.067 | |||
| R2 | 0.082 | 0.091 | 0.082 | 0.091 | 0.095 | 0.104 |
| + p < 0.1, * p < 0.05, ** p < 0.01, *** p < 0.001 | ||||||
Race Effects (w/ Income Interaction) on Claims Amount
| R&IM 1 | R&IM 1 (full) | R&IM 2 | R&IM 2 (full) | R&IM 3 | R&IM 3 (full) | |
|---|---|---|---|---|---|---|
| Percent white | -0.059 | 1.396 | ||||
| Percent black | 0.150+ | -2.543* | ||||
| Percent hispanic | -0.214* | 0.327 | ||||
| Race*Income: <35 | -1.735 | 2.893** | -0.650 | |||
| Race*Income: 35-50 | -1.711 | 2.898** | -0.509+ | |||
| Race*Income: 50-75 | -0.711 | 1.685 | -0.804* | |||
| Race*Income: 75-100 | -1.203 | 2.069* | -0.629*** | |||
| Race*Income: >150 | -0.619 | 3.209+ | -1.237*** | |||
| Flood depth | -0.281*** | -0.289*** | -0.282*** | -0.291*** | -0.281*** | -0.293*** |
| Flood duration | -0.055+ | -0.060* | -0.055+ | -0.060+ | -0.056* | -0.064* |
| Reopened | -0.110 | -0.131 | -0.109 | -0.141 | -0.115 | -0.131 |
| Catastrophe | 0.235+ | 0.213 | 0.237 | 0.150 | 0.280+ | 0.242 |
| SFHA zone | 0.612* | 0.588* | 0.616* | |||
| Elevated | -0.875*** | -0.824*** | -0.883*** | |||
| Floodproofed | -2.525*** | -2.481*** | -2.526*** | |||
| Population | -0.074 | -0.077 | -0.071 | |||
| R2 | 0.082 | 0.108 | 0.084 | 0.116 | 0.084 | 0.098 |
| + p < 0.1, * p < 0.05, ** p < 0.01, *** p < 0.001 | ||||||
Income Effects on Claims Closed without Payment
| IM 1 | IM 1 (full) | IM 2 | IM 2 (full) | IM 3 | IM 3 (full) | |
|---|---|---|---|---|---|---|
| Med Income ($thous) | 0.001 | 0.000 | ||||
| Income: <35 | -0.005 | -0.002 | ||||
| Income: 35-50 | 0.003 | 0.004 | ||||
| Income: 50-75 | 0.004 | 0.003 | ||||
| Income: 75-100 | 0.004 | 0.003 | ||||
| Income: >150 | 0.002 | 0.004 | ||||
| Pct Poverty | -0.001 | 0.000 | ||||
| Flood depth | 0.004 | 0.004+ | 0.004 | 0.004+ | 0.004 | 0.004+ |
| Damage | -0.270*** | -0.270*** | -0.270*** | -0.270*** | -0.270*** | -0.270*** |
| Flood duration | -0.002*** | -0.002*** | -0.002*** | -0.002*** | -0.002*** | -0.002*** |
| Reopened | -0.014* | -0.013* | -0.014* | -0.013* | -0.014* | -0.013* |
| Catastrophe | -0.028*** | -0.030*** | -0.029*** | -0.030*** | -0.029*** | -0.030*** |
| SFHA zone | 0.013 | 0.013 | 0.013 | |||
| Elevated | 0.000 | 0.000 | 0.000 | |||
| Floodproofed | -0.082*** | -0.082*** | -0.082*** | |||
| Population | -0.001 | -0.001 | -0.001 | |||
| R2 | 0.175 | 0.177 | 0.176 | 0.177 | 0.175 | 0.177 |
| + p < 0.1, * p < 0.05, ** p < 0.01, *** p < 0.001 | ||||||
Wealth Effects on Claims Closed without Payment
| WM 1 | WM 1 (full) | WM 2 | WM 2 (full) | WM 3 | WM 3 (full) | |
|---|---|---|---|---|---|---|
| Property value | -0.011*** | -0.011*** | ||||
| Homeowners | 0.003 | -0.001 | ||||
| College Educated | 0.018*** | 0.018*** | ||||
| Flood depth | -0.004 | -0.003 | -0.004 | -0.003 | -0.004 | -0.003 |
| Flood duration | -0.006*** | -0.004*** | -0.006*** | -0.004*** | -0.005*** | -0.004*** |
| Reopened | -0.139*** | -0.135*** | -0.138*** | -0.134*** | -0.139*** | -0.135*** |
| Catastrophe | -0.109*** | -0.105*** | -0.109*** | -0.106*** | -0.111*** | -0.107*** |
| SFHA zone | -0.043** | -0.043** | -0.041** | |||
| Elevated | -0.017+ | -0.017+ | -0.016+ | |||
| Floodproofed | -0.078 | -0.078 | -0.087+ | |||
| Population | 0.002 | 0.002 | 0.003 | |||
| R2 | 0.049 | 0.056 | 0.049 | 0.055 | 0.050 | 0.057 |
| + p < 0.1, * p < 0.05, ** p < 0.01, *** p < 0.001 | ||||||
Race Effects (w/ Income Interaction) on Claims Closed without Payment
| R&IM 1 | R&IM 1 (full) | R&IM 2 | R&IM 2 (full) | R&IM 3 | R&IM 3 (full) | |
|---|---|---|---|---|---|---|
| Percent white | -0.013 | -0.013 | ||||
| Percent black | 0.017 | 0.016 | ||||
| Percent hispanic | 0.005 | 0.005 | ||||
| Race*Income: <35 | 0.011 | 0.009 | -0.016 | -0.014 | -0.002 | -0.002 |
| Race*Income: 35-50 | 0.009 | 0.008 | -0.013 | -0.012 | -0.003 | -0.003 |
| Race*Income: 50-75 | 0.007 | 0.007 | -0.009 | -0.009 | -0.004 | -0.005 |
| Race*Income: 75-100 | 0.010 | 0.010 | -0.007 | -0.006 | -0.007 | -0.008 |
| Race*Income: >150 | 0.009 | 0.012 | -0.008 | -0.012 | -0.011 | -0.013+ |
| Flood depth | 0.004 | 0.005+ | 0.004 | 0.004+ | 0.004 | 0.004+ |
| Damage | -0.270*** | -0.270*** | -0.271*** | -0.271*** | -0.270*** | -0.270*** |
| Flood duration | -0.002*** | -0.002*** | -0.002*** | -0.002*** | -0.002*** | -0.002*** |
| Reopened | -0.014* | -0.013* | -0.014* | -0.013* | -0.014* | -0.013* |
| Catastrophe | -0.028*** | -0.030*** | -0.028*** | -0.030*** | -0.028*** | -0.030*** |
| SFHA zone | 0.013 | 0.013 | 0.013 | |||
| Elevated | 0.001 | 0.000 | 0.000 | |||
| Floodproofed | -0.081*** | -0.081*** | -0.083*** | |||
| Population | -0.001 | -0.001 | -0.001 | |||
| R2 | 0.176 | 0.177 | 0.176 | 0.177 | 0.175 | 0.177 |
| + p < 0.1, * p < 0.05, ** p < 0.01, *** p < 0.001 | ||||||