Background on Medicaid Expansion and the ACA

Data sources

We’ll use two main data sources here:

Data on which states expanded Medicaid (and when

Available from Kaiser Family Foundation

Data on insurance status and source of health insurance by state

Available from the American Community Survey
These data can be tricky to work with due to their size, but there are some handy tricks in R

Data sources

Code and links available at the Insurance Access GitHub repository

Medicaid Expansion

Directly downloaded from KFF website
Just a raw .csv file

Insurance status and source

Data from the American Community Survey
CPS data also available but questions changed in 2014
Easiest way to access ACS data is through a Census API and the acs package…details on the GitHub repo

What is an API?

Stands for application programming interface
An official way for one computer to request information from another
Often requires a code for external program/server to validate the request

Describing the data

First let’s take a look at the final dataset

head(ins.dat %>% arrange(year, State))

# A tibble: 6 × 20
  State       year adult_pop ins_employer ins_direct ins_medicare ins_medicaid
  <chr>      <dbl>     <dbl>        <dbl>      <dbl>        <dbl>        <dbl>
1 Alabama     2012   2937335      1528419     180043        56890       190312
2 Alaska      2012    460946       222769      15608         2027        28177
3 Arizona     2012   3866694      1867954     263076        41042       428972
4 Arkansas    2012   1761365       871970     106277        39157       114012
5 California  2012  23798381     12015639    1824564       180861      2275053
6 Colorado    2012   3270163      1801613     303179        27254       213045
# ℹ 13 more variables: uninsured <dbl>, expand_ever <lgl>, date_adopted <date>,
#   expand_year <dbl>, expand <lgl>, perc_private <dbl>, perc_public <dbl>,
#   perc_ins <dbl>, perc_unins <dbl>, perc_employer <dbl>, perc_medicaid <dbl>,
#   perc_medicare <dbl>, perc_direct <dbl>

Summary stats

And now for some basic summary stats (pooling all years):

R Code

sum.vars <- ins.dat %>% select('Uninsured'=perc_unins, 'Direct Purchase'=perc_direct, 'Medicaid'=perc_medicaid)

datasummary(All(sum.vars) ~ Mean + SD + Histogram, data=sum.vars)

	Mean	SD	Histogram
Uninsured	0.14	0.06	▃▇▇▇▆▄▂▂▁
Direct Purchase	0.08	0.02	▁▄▆▇▆▂▂ ▁
Medicaid	0.10	0.06	▇▇▅▃▁

Uninsurance over time

R Code

ins.dat %>% group_by(year) %>% summarize(mean=mean(perc_unins)) %>%
  ggplot(aes(x=year,y=mean)) + geom_line() + geom_point() + theme_bw() +
  labs(
    x="Year",
    y="Fraction Uninsured",
    title="Share of Uninsured over Time"
  ) +
  geom_vline(xintercept=2013.5, color="red")

Direct purchase over time

R Code

ins.dat %>% group_by(year) %>% summarize(mean=mean(perc_direct)) %>%
  ggplot(aes(x=year,y=mean)) + geom_line() + geom_point() + theme_bw() +
  labs(
    x="Year",
    y="Fraction with Direct Purchase",
    title="Share of Direct Purchase Insurance over Time"
  ) +
  geom_vline(xintercept=2013.5, color="red")

Medicaid over time

R Code

ins.dat %>% group_by(year) %>% summarize(mean=mean(perc_medicaid)) %>%
  ggplot(aes(x=year,y=mean)) + geom_line() + geom_point() + theme_bw() +
  labs(
    x="Year",
    y="Fraction with Medicaid",
    title="Share of Medicaid Insurance over Time"
  ) +
  geom_vline(xintercept=2013.5, color="red")

Main takeaways

Large reduction in uninsured population following ACA
Biggest gains going to direct purchase (exchanges) and Medicaid (expansion)

But what amount of extra insurance is due to Medicaid expansion? In other words, who got insurance through Medicaid that wouldn’t have gotten it otherwise?

What does the literature say

The Kaiser Family Foundation has some great info on this…

KFF Medicaid Coverage
KFF Report on ACA Expansion
Health Insurance and Mortality (not what we’re discussing here but still important)

Background on Medicaid Expansion and the ACA

Affordable Care Act

Background

Background

Employer provided insurance

Employer provided insurance

How did the ACA change things?

How did the ACA change things?

Change in Insurance Type over Time

Data for this (final!) homework assignment

Data sources

Data sources

Medicaid Expansion

Insurance status and source

What is an API?

Describing the data

Summary stats

Uninsurance over time

Direct purchase over time

Medicaid over time

Main takeaways

What does the literature say